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Feeding broiler chickens wheat and barley diets containing whole, ground and pelleted grain
Feeding Broiler Chickens Wheat and Barley Diets Containing Whole, Ground and Pelleted Grain1 C. D. Bennett,*,1,2,3 H. L. Classen,* and C. Riddell‡ *Department of Animal & Poultry Science, University of Saskatchewan, Saskatchewan, Canada, S7N 5B5; and ‡Department of Veterinary Pathology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada, S7N 5B4 mash supplements slowed growth at all ages and lowered mortality caused by sudden death syndrome and ascites plus right heart failure. Cumulative feed:gain was increased by feeding mash supplements in Trial 1. Total weight gain was unaffected by feeding whole wheat but was decreased by most levels of whole barley. Wholegrain diets increased cumulative feed:gain. Feeding whole wheat decreased skeletal problems. Whole-grain diets increased gizzard size but did not alter carcass yield. Feeding whole-grain and mash supplements caused at least a temporary loss in growth rate and feed efficiency but in some cases improved bird health.
(Key words: whole wheat, whole barley, mash, pellet, broiler) 2002 Poultry Science 81:995–1003
the energy availability of whole and ground wheat has produced contradictory results, with whole wheat having lower true metabolizable energy but similar apparent metabolizable energy concentration as ground wheat (Salah Uddin et al., 1996). In the present studies, the effect of grain form (whole, mash, or crumbled and pelleted) on growth rate, feed conversion, mortality, and carcass yield of broiler chickens fed wheat and barley based diets was determined. The rate at which whole grain could be increased in the feed as broilers aged was also examined.
INTRODUCTION In the past decade, some poultry producers in Europe, Australia, and Canada have started to add whole wheat on-farm to increase the use of locally grown grains and reduce trucking and feed milling costs (Cumming, 1994). The use of whole grain is not new, however, and early research (McIntosh et al., 1962a) indicated that growing birds could be fed whole grain with little or no loss in performance. More recently, Bennett et al. (1995) and Rose et al. (1995) reported that broiler chickens fed whole-wheat diets had the same market weight and feed conversion as birds fed pelleted wheat diets. Svihus et al. (1997) found in two trials that broiler chickens fed whole barley grew at the same rate but had a higher feed:gain ratio than those fed rolled barley. In a third trial by these researchers, birds fed whole barley gained more weight and had the same feed conversion as birds fed ground barley. Testing of
MATERIALS AND METHODS Trial 1 A total of 2,256 commercial broiler cockerels were housed in four environmentally controlled rooms, with 12 pens per room and 47 chicks in each of the 2.3- × 2-m pens. The birds were reared under an increasing lighting program (Classen and Riddell, 1989). Initial room temperature was 32 C and was then gradually decreased according to usual brooding practices. Hot water pipes provided supplemental heat. All birds received a starter ration from 0 to 13 d of age, a grower ration from 13 to 27 d, and a finisher ration from 27 to 48 d (Table 1). The trial was designed as a 6 × 2 factorial with six combinations of whole grain and two forms of supplement (Table 2). The ingredient composition
2002 Poultry Science Association, Inc. Received for publication October 22, 2001. Accepted for publication January 30, 2002. 1 Trial 1 was previously published as an abstract: Bennett, C. D. and H. L. Classen. 1997. Feeding whole wheat in combination with mash or pelleted supplements. Poult. Sci. 76(Suppl. 1):43. (Abstr.). 2 Present Address: Manitoba Agriculture and Food, 545 University Crescent, Winnipeg, Manitoba, Canada, R3T 5S6. 3 To whom correspondence should be addressed: cbennett@ gov.mb.ca.
995
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ABSTRACT The effect of grain form (whole, mash, or pelleted) on the live performance of broiler chickens was determined. In the first trial, six regimens compared the feeding of whole wheat: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27d. Each feeding regimen was replicated with steam-pelleted and mash supplements. None of the feed was diluted. The second trial was similar, except that whole barley was fed instead of whole wheat. Feeding
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BENNETT ET AL. TABLE 1. Dietary treatments–percentages of whole grain in rations (Trials 1 and 2)1 Age (d)
Level of whole grain (wheat in Trial 1, barley in Trial 2)
Trial 1
Trial 2
1
2
3
4
5
6
0–6 6–13 13–27 27–48
0–7 7–14 14–28 28–49
0 0 0 0
0 5 20 35
0 5 35 50
5 20 35 50
0 5 50 65
5 20 50 65
1 Each level of whole-wheat feeding was replicated with the remaining ingredients in the diets being fed in steam-pelleted or mash form. When steam-pelleting was used, the portion of the feed not fed as whole grain was fed as crumbles in the first two periods and as pellets in the last two periods.
the four rooms in the study. For the treatments with steampelleted supplements, the portion of the diet that was not whole grain was fed as a crumble in the starter and grower rations and as a pellet in the finisher ration. After being steam-pelleted, the crumbles or pellets were blended with the whole grain in a ribbon mixer. When mash supplements were used, the grain portion of the supplement was coarsely ground by a hammermill with a 0.64-cm screen. No insoluble grit was fed in any of the treatments. The birds were pen-weighed at 0, 6, 13, 27, and 48 d, and feed consumption was determined for each of these periods. Sixteen birds per treatment, four birds per pen, were selected at 41 d, weighed, fasted overnight, and then killed and processed at 42 d of age to determine carcass yield and weight of internal organs. For the selected birds,
TABLE 2. Percentage ingredient composition and calculated nutritional values of experimental diets in Trials 1 and 2 Trial 1 Ingredient 1
Wheat Barley1 Soybean meal (48% CP) Meat and bone meal Limestone Dicalcium phosphate Canola oil Tallow Salt DL-Methionine Lysine HCL L-Threonine Vitamin-mineral premix2 Feed enzyme3 Ethoxyquin Zinc bacitracin4 Coxistac5 Calculated nutrient content Crude protein, % AME, kcal/kg Methionine + cystine, % Lysine, %
Trial 2
Starter
Grower
Finisher
Starter
Grower
Finisher
55.30 10.00 22.79 5.00 1.05 0.89 1.00 2.79 0.25 0.21 0.20 0.02 0.17 0.10 0.08 0.05 0.10
61.98 15.00 14.00 5.00 1.06 0.92 0.94 0.00 0.25 0.16 0.17 0.03 0.17 0.10 0.08 0.05 0.10
74.25 10.00 8.50 3.50 1.24 1.18 0.30 0.00 0.27 0.08 0.15 0.03 0.17 0.10 0.08 0.05 0.10
39.30 25.00 24.41 5.00 1.02 0.88 3.29 0.00 0.26 0.20 0.14 0.00 0.17 0.10 0.08 0.05 0.10
26.00 50.00 12.68 7.00 0.80 0.62 1.82 0.00 0.24 0.16 0.17 0.02 0.17 0.10 0.08 0.05 0.10
16.44 65.00 8.00 6.92 0.79 0.65 1.30 0.00 0.24 0.06 0.09 0.00 0.17 0.10 0.08 0.05 0.00
22.5 3,000 0.86 1.25
19.8 2,900 0.72 1.00
17.4 2,900 0.58 0.81
22.5 2,950 0.87 1.25
19.0 2,850 0.72 1.00
17.0 2,800 0.58 0.81
1 Depending on the dietary treatment, some of the wheat in Trial 1 and barley in Trial 2 was fed as whole grain. The percentage whole grain in the complete diets for each treatment is displayed in Table 1. 2 The vitamin mineral mix supplied the following per kilogram of complete feed: 11,500 IU vitamin A; 2,600 IU vitamin D3; 40 IU vitamin E; 2.5 mg menadione; 2.5 mg thiamine; 10 mg riboflavin; 84 mg niacin; 4 mg pyridoxine; 0.016 mg vitamin B12; 15.4 mg pantothenic acid; 1.1 mg folic acid; 0.14 mg biotin; 0.125 mg antioxidant; 56 mg iron, 77 mg zinc; 95 mg manganese; 7 mg copper; 0.9 mg iodine; 0.21 mg selenium. 3 Avizyme TX in Trial 1 and Avizyme SX in Trial 2. Both were supplied by Finfeeds International Ltd, Marlborough, Wiltshire, 777 UK. 4 Davis & Lawrence Animal Nutrition, Cambridge, ON, Canada, N3C 2W4. 5 Pfizer Canada Inc., London, ON, Canada, N6A 4C6.
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of the diets was identical for all treatments, with the only difference being in the proportion of the total diet that was fed as whole wheat and whether the portion of the diet that was not whole wheat was fed as ground mash or crumbles and pellets. Six levels of whole wheat were fed: 1) 0% whole wheat from 0 to 48 d; 2) 0% whole wheat at 0 d, 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 0% whole wheat at 0 d, 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% whole wheat at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 0% whole wheat at 0 d, 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% whole wheat at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. Each of the six levels of whole wheat was replicated with steam-pelleted and mash supplements. Each combination of level of whole grain and supplement form was replicated four times with one pen in each of
FEED FORM FOR BROILER CHICKENS
the eviscerated carcass, crop, proventriculus, gizzard (with and without digesta contents), small intestine, and abdominal fat pad were weighed. All birds that died during the trial were weighed and stored at 5 C until postmortem examination. Feed:gain ratio was corrected for mortality by including the weight of the dead birds in the body weight gain.
Trial 2
Statistical Analyses Both trials were analyzed as 6 × 2 factorial designs with level of whole grain and form of supplement as main effects. Statistical analyses were computed with SAS software (1990). When the analysis of variance was significant, Duncan’s multiple-range test was used to separate the means. Differences between treatment means were considered statistically significant at P < 0.05.
RESULTS Trial 1 Birds fed mash supplements had lower body weight gains than those fed pelleted supplements at all ages and cumulatively over the life of the flock (Table 3). Feeding 5% whole wheat from 0 to 6 d had no influence on weight gain. At 6 to 13 d, a significant interaction was observed, and the growth response to feeding of whole wheat depended on the type of supplement used. During this time, the birds fed 20% whole wheat (levels 4 and 6) combined with a pelleted supplement grew slower than birds fed 0 or 5% whole grain and pelleted supplement (levels 1, 2, 3 and 5). Addition of whole wheat to a mash supplement did not slow growth during this period. At 13 to 27 d, a similar interaction occurred; some of the birds fed a pelleted supplement and 35 or 50% whole wheat (levels 4, 5 and 6) gained less weight than birds fed no whole grain
(level 1). Again, no differences due to whole-grain level were observed for the broilers fed mash-based diets. Unlike 6 to 13 d, the birds fed 20% whole grain and a pelleted supplement (level 2) grew at a rate similar to those fed just pellets. From 27 to 48 d, feeding 35 to 65% whole wheat had no effect on body weight gain, regardless of the type of supplement used. Total body weight gain was unaffected by feeding whole wheat. Compared to a pelleted supplement, feeding a mash supplement increased feed:gain ratio from 6 to 27 d, had no effect from 27 to 48 d, and increased cumulative feed:gain ratio (2.06 vs. 2.03; Table 4). At 0 to 27 d, feeding 20% or more whole grain increased feed:gain ratio compared to the rations with no whole grain. At 27 to 48 d, broilers fed 35% whole wheat (level 2) and some of those fed 50% whole wheat (level 4) had similar feed conversions to birds fed no whole wheat (level 1). The birds fed 65% whole wheat in the finisher feed (levels 5 and 6) had a higher feed:gain ratio than birds fed finishers containing 0 or 35% whole wheat (levels 1 and 2). Feed:gain ratio for the life of the flock was lower for birds reared on the control rations (level 1) than any of the birds reared on whole-grain diets. Broilers fed the highest two levels of whole wheat had a higher cumulative feed:gain ratio than most of the other treatments in which whole grain was used (level 5 vs. levels 2 to 4; level 6 vs. levels 2 and 4). Feeding a mash supplement reduced mortality due to sudden death syndrome and increased skeletal and leg problems but did not change total mortality compared to feeding a pelleted supplement (Table 5). Feeding almost any amount of whole wheat (levels 2, 3, 4, and 6) reduced skeletal and leg problems compared to not feeding any whole grain but did not change total mortality. Sudden death syndrome and skeletal and leg problems accounted for approximately two-thirds of the mortality in the trial. Feeding mash supplements compared to pelleted supplements resulted in a small but significant increase in the weight of the gizzard, with and without digesta contents, as a percentage of the live weight of the bird (Table 6). Eviscerated carcass yield and the percentage weight of other organs were unaffected by feeding mash supplements. Feeding some levels of whole wheat (levels 3, 4, and 5) increased the percentage of offal compared to not feeding any whole wheat but did not alter eviscerated carcass yield. Feeding whole wheat had no overall effect on percentage proventriculus, but a significant interation of whole-wheat level × supplement form did occur, and some inconsistent differences were observed (data not shown). For birds fed pelleted supplements, birds fed the sixth level of whole wheat had larger proventriculi than those fed the third, fourth, or fifth levels of whole wheat. When mash supplements were used, birds fed the fourth level of whole wheat had larger proventriculi than those fed the second level of whole wheat. Crop, small intestine, and abdominal fat pad weights were unaffected by wholegrain level or form of supplement. The most noticeable dietary effects on organ weight were observed in the response of gizzard weight to different levels of whole grain. Cockerels fed no whole wheat had
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A total of 2,208 commercial broiler cockerels was housed and reared similarly to Trial 1, except that 46 instead of 47 chicks were placed per pen. All birds received barleybased starter ration from 0 to 14 d of age, grower ration from 14 to 28 d, and finisher ration from 28 to 49 d (Table 1). As in the previous trial, Trial 2 was designed as a 6 × 2 factorial with six levels of whole grain and two forms of supplement (Table 2). The same six whole-grain feeding regimens were used as in Trial 1, except that whole barley was fed instead of whole wheat and the whole-grain levels were changed at 1 d of age later than Trial 1. The steampelleted and mash supplements were produced in a manner and form similar to Trial 1. No insoluble grit was fed. The birds were pen weighed at 0, 7, 14, 28, and 49 d of age, and feed consumption was determined for each of these time periods. All birds that died during the trial were weighed and stored at 5 C until postmortem examination. The feed:gain ratio was corrected for mortality by including the weight of the dead birds in the body weight gain.
997
998
BENNETT ET AL. TABLE 3. Body weight gain (g) of broiler cockerels fed different levels of whole wheat and pelleted or mash supplements (Trial 1) Age (d) 1
Level of whole wheat
0–6
a
13–27
27–48
0–48
102 104 104 103 105 99
235 238a 234a 224bc 232ab 224c
904 894 893 899 901 894
1,641 1,618 1,598 1,609 1,593 1,587
2,882 2,853 2,829 2,838 2,831 2,804
108a 98b
240a 223b
933a 862b
1,628a 1,588b
2,909a 2,770b
108 97 107 101 111 97 106 100 110 101 103 96 1.1
244a 226c 252a 224c 249a 220c 231bc 222c 241ab 223c 227c 222c 1.8
957a 852c 934ab 854c 934ab 852c 931b 868c 927b 875c 918b 869c 5.8
1,670 1,613 1,644 1,591 1,614 1,583 1,644 1,574 1,616 1,570 1,577 1,596 8.1
2,978 2,788 2,937 2,769 2,908 2,751 2,912 2,764 2,893 2,769 2,825 2,783 13.8
NS *** NS
*** *** **
NS *** **
NS * NS
NS *** NS
a–c
Means with different superscripts are significantly different. The six levels of whole wheat compared were as follows: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. NS P > 0.05. *P < 0.05. **P < 0.01. ***P < 0.001. 1
TABLE 4. Feed:gain of broiler cockerels fed different levels of whole wheat and pelleted or mash supplements (Trial 1) Age (d) 1
Level of whole wheat 1 2 3 4 5 6 Type of supplement Pelleted Mash SEM P-value Level Supplement Level × supplement a–d
0–6
6–13
13–27
1.251 1.203 1.211 1.215 1.198 1.235
c
1.321 1.325bc 1.341abc 1.378a 1.344abc 1.364ab
c
27–48
1.620 1.666ab 1.673ab 1.654b 1.694a 1.694a
2.366 2.407bc 2.446ab 2.427abc 2.482a 2.485a
1.991d 2.025c 2.050bc 2.038c 2.073ab 2.082a
1.215 1.223 0.0092
1.331b 1.359a 0.0065
1.630b 1.704a 0.0077
2.446 2.425 0.0107
2.028b 2.058a 0.0061
NS NS NS
* * NS
*** *** NS
** NS NS
*** ** NS
c
0–48
Means with different superscripts are significantly different. The six levels of whole wheat compared were as follows: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. NS P > 0.05. *P < 0.05. **P < 0.01. ***P < 0.001. 1
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1 2 3 4 5 6 Type of supplement Pelleted Mash Level of whole wheat × type of supplement 1 × Pellet 1 × Mash 2 × Pelleted 2 × Mash 3 × Pelleted 3 × Mash 4 × Pelleted 4 × Mash 5 × Pelleted 5 × Mash 6 × Pelleted 6 × Mash SEM P-value Level Supplement Level × supplement
6–13
999
FEED FORM FOR BROILER CHICKENS TABLE 5. Cause of mortality from 0 to 48 d of broiler cockerels fed different levels of whole wheat and pelleted or mash supplements (Trial 1) Type of supplement
Level of whole wheat6
P-value
Cause of mortality
1
2
3
4
5
6
Pelleted
Mash
SEM
Level
Supplement
Level × supplement
SDS1 Ascites and RHF2 Skeletal and leg3 Early mortality4 Infectious Other NVL5 Total
3.99 1.06 3.19a 0.00 0.00 0.27 0.53 9.04
4.52 0.53 1.06b 1.33 0.53 0.80 0.00 8.78
4.52 0.53 0.53b 0.27 0.00 0.80 0.80 7.45
3.46 0.53 1.06b 0.53 0.00 0.53 0.53 6.65
2.39 1.33 2.39ab 1.06 0.53 0.53 0.80 9.04
1.86 1.86 1.06b 1.33 0.00 0.53 0.00 6.65
4.08a 1.33 0.98b 0.62 0.09 0.71 0.71 8.51
2.84b 0.62 2.13a 0.89 0.27 0.44 0.18 7.36
0.345 0.228 0.281 0.205 0.107 0.176 0.167 0.693
NS NS * NS NS NS NS NS
* NS * NS NS NS NS NS
NS NS NS NS NS NS NS NS
Means with different superscripts are significantly different; P < 0.05. SDS = Sudden death syndrome. 2 RHF = Right heart failure. 3 Skeletal and leg included valgus varus leg deformity, rotated tibia, tibial dyschondroplasia, kinky back, and broken bones. 4 Early mortality included yolk sac infection, dehydration, and starve outs. 5 NVL = No visible lesions. 6 The six levels of whole wheat compared were as follows: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. NS P > 0.05. *P < 0.05. a,b 1
birds fed the fourth level of whole wheat). A significant interaction indicated that type of supplement influenced the effect of whole grain on gizzard weight, with and without digest (data not displayed). For pelleted supplements, the control birds had smaller gizzards than birds
TABLE 6. Dressed and eviscerated carcass yields and relative organ weights at 41 d of broiler cockerels fed different levels of whole wheat and pelleted or mash supplements (Trial 1) Carcass/organ weight (% of live bird weight)
Level of whole wheat4 1 2 3 4 5 6 Type of supplement Pelleted Mash SEM P-value Level Supplement Level × supplement a–c
Dressed carcass1
Eviscerated carcass2
Offal3
Crop
Proventriculus
Gizzard
Gizzard + digesta
Small intestine
Abdominal fat pad
78.27 78.10 78.48 78.66 78.33 78.87
65.71 65.14 65.04 65.62 64.99 65.52
12.56b 12.94ab 13.44a 13.04ab 13.34a 13.35a
0.26 0.26 0.25 0.26 0.27 0.26
0.33 0.33 0.34 0.35 0.34 0.36
1.37c 1.62b 1.88a 1.76a 1.87a 1.83a
1.55c 1.93b 2.18a 2.05ab 2.17a 2.13a
2.06 2.03 2.15 2.06 2.10 2.03
1.64 1.70 1.80 1.66 1.76 1.69
78.44 78.47 0.104
65.46 65.21 0.121
12.97b 13.26a 0.072
0.26 0.26 0.003
0.34 0.34 0.004
1.67b 1.78a 0.021
1.91b 2.11a 0.026
2.01 2.10 0.017
1.73 1.69 0.033
NS NS NS
NS NS NS
** * NS
NS NS NS
NS NS **
*** *** *
*** *** **
NS NS NS
NS NS NS
Means with different superscripts are significantly different. Dressed carcass = carcass with feathers, head, neck and feet removed. 2 Eviscerated carcass = dressed carcass with viscera removed. 3 Offal = dressed carcass − eviscerated carcass weight. 4 The six levels of whole wheat compared were as follows: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. NS P > 0.05. *P < 0.05. **P < 0.01. ***P < 0.001. 1
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smaller gizzards, with or without digesta, than those of birds fed any whole wheat. Birds fed a low amount of whole wheat (level 2) had full and empty gizzard weights lower than almost all of the birds fed higher levels of whole wheat (except compared to the empty gizzard weight of
1000
BENNETT ET AL. TABLE 7. Body weight gain (g) of broiler cockerels fed different levels of whole barley and pelleted or mash supplements (Trial 2) Age (d) 0–7
7–14
14–28
28–49
0–49
79a 72c 71c 78ab 73bc 78ab
207 204 204 204 203 205
831 817 825 828 823 836
1,670a 1,593b 1,618b 1,591b 1,607b 1,610b
2,787a 2,686b 2,718b 2,702b 2,706b 2,729ab
79a 71b
211a 198b
852a 802b
1,634a 1,596b
2,776a 2,667b
85a 72b 74b 69b 71b 71b 86a 71b 74b 73b 85a 72b 1.0
212 202 211 198 206 202 215 194 208 198 216 195 1.3
866a 796e 848ab 787e 840abc 810de 861a 795e 830bcd 816cde 864a 807de 4.6
1,709 1,632 1,611 1,575 1,646 1,590 1,621 1,562 1,607 1,607 1,606 1,614 7.8
2,872 2,702 2,744 2,682 2,764 2,672 2,783 2,622 2,720 2,693 2,771 2,688 12.5
*** *** *
NS *** NS
NS *** *
* ** NS
* *** NS
1
a–e
Means with different superscripts are significantly different. The six levels of whole barley compared were as follows: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. NS P > 0.05. *P < 0.05. **P < 0.01. ***P < 0.001. 1
fed any whole wheat (levels 2 to 6). For mash supplements, the control birds had gizzard weights similar to birds fed the least whole wheat (level 2). Some other inconsistent differences were observed among the different types of supplement, but the basic trend was for gizzard weight to increase as more whole grain was fed. Numerically, the differences in gizzard weight accounted for most of the differences in eviscerated carcass yield among the birds fed different levels of whole grain.
Trial 2 As in Trial 1, feeding a mash supplement decreased body weight gain in all periods and reduced total body weight gain compared to a pelleted supplement (Table 7). Feeding whole barley decreased body weight gain overall and during many periods. From 0 to 7 d, however, the response to whole barley appeared to be positive and the broilers fed 5% whole barley plus a pelleted supplement (levels 4 and 6) had a greater weight gain than some of the birds fed no whole barley at that age (levels 2, 3, and 5). A significant interaction indicated that this improvement only occurred for birds fed pelleted supplements. At 7 to 14 d, feeding whole barley had no effect on weight gain
even though some of the birds were fed 20% whole grain during this time. From 14 to 28 d, feeding whole barley had no overall effect on weight gain but a significant interaction was observed. The birds fed a pelleted supplement and 50% whole barley (level 5) had a lower body weight gain than the other birds fed pelleted supplements, but no significant differences were observed when whole barley was added to mash supplements. From 28 to 49 d of age, all of the birds, even those fed 35% whole barley, grew slower than those fed the control diets, and no influence of supplement form on this reduction in growth rate was observed. Compared to the birds on the control diets (level 1), total body weights gain were reduced for all birds fed whole barley, except for those fed the maximum level of whole barley (level 6). Feed:gain ratio was similar at all ages and in total for birds fed mash and pelleted supplements (Table 8). Feeding 5% whole barley from 0 to 7 d (levels 4 and 6) improved feed conversion compared to several of the treatments in which no whole grain was fed (levels 2, 3, and 5); this pattern was similar to the one observed for body weight gain at the same age. From 7 to 14 d, feeding whole barley had no impact on feed conversion, but at 14 to 28 d of age most of the birds fed whole barley (levels 2, 4, 5, and 6)
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Level of whole barley 1 2 3 4 5 6 Type of supplement Pelleted Mash Level of whole barley × type of supplement 1 × Pelleted 1 × Mash 2 × Pelleted 2 × Mash 3 × Pelleted 3 × Mash 4 × Pelleted 4 × Mash 5 × Pelleted 5 × Mash 6 × Pelleted 6 × Mash SEM P-value Level Supplement Level × supplement
1001
FEED FORM FOR BROILER CHICKENS TABLE 8. Feed:gain ratio of broiler cockerels fed different levels of whole barley and pelleted or mash supplements (Trial 2) Age (d) 1
Level of whole barley
7–14
14–28
1.283 1.457a 1.398ab 1.277c 1.394ab 1.329bc
1.249 1.281 1.280 1.289 1.285 1.293
c
1.635 1.661ab 1.651bc 1.665ab 1.674a 1.675a
2.327 2.360bc 2.384ab 2.408a 2.385ab 2.387ab
2.004b 2.037a 2.044a 2.056a 2.053a 2.050a
1.349 1.364
1.284 1.275
1.661 1.659
2.385 2.365
2.042 2.039
1.250 1.317 1.485 1.430 1.416 1.379 1.238 1.316 1.411 1.377 1.294 1.364 0.0157
1.259 1.239 1.257 1.306 1.292 1.268 1.311 1.268 1.274 1.295 1.310 1.276 0.0058
1.618 1.651 1.662 1.660 1.648 1.654 1.669 1.660 1.682 1.667 1.687 1.663 0.0034
2.325d 2.328cd 2.365bcd 2.356bcd 2.385abcd 2.383abcd 2.399abc 2.418ab 2.394abcd 2.376abcd 2.445a 2.329cd 0.0075
1.994d 2.015cd 2.032bcd 2.041abc 2.045abc 2.044abc 2.046abc 2.066ab 2.056abc 2.050abc 2.080a 2.021cd 0.0047
** NS NS
NS NS NS
** NS NS
* NS *
** NS *
c
28–49 c
0–49
a–d
Means with different superscripts are significantly different. The six levels of whole barley compared were as follows: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. NS P > 0.05. *P < 0.05. **P < 0.01. ***P < 0.001. 1
had a higher feed:gain ratio than the birds on the control rations. Use of whole-barley diets improved by 28 to 49 d, and the improvement in feed efficiency was most noticeable with mash supplements (significant interaction of whole-grain level × supplement form). At this age, most of the birds fed mash supplements had a similar feed:gain ratio (levels 1, 2, 3, 5, and 6). For pelleted supplements, the birds fed no whole barley had a lower feed:gain ratio than some of the birds fed high amounts of whole barley (levels 4 and 6), and the birds fed a low amount of whole barley (level 2) had a lower feed:gain ratio than birds fed the most whole barley (level 6). The effect of feeding whole barley on cumulative feed:gain ratio was similar to that observed at 28 to 49 d, and a significant interaction occurred between supplement form and level of whole grain. For broilers fed mash supplements, most of the birds had cumulative feed conversions that were similar (levels 1, 2, 3, 5, and 6). When pelleted supplements were used, the birds fed the control rations had a feed:gain ratio lower than birds fed high amounts of whole grain (levels 3 to 6). Chickens fed a low amount of whole barley and pelleted supplement (level 2) had a lower feed:gain ratio than birds fed the highest level of whole grain (level 6). Mortality due to ascites and right heart failure was reduced by feeding a mash supplement, but total mortality
was unaffected (Table 9). Feeding whole barley did not affect cause of mortality or total mortality. As in Trial 1, approximately two-thirds of the mortality was due to sudden death syndrome and skeletal and leg problems.
DISCUSSION Compared to a pelleted supplement, feeding a wheat or barley mash supplement slowed growth rate at all ages but had almost no effect on feed efficiency. Barley mash supplements had no effect on cumulative feed:gain ratio, and wheat mash supplements increased feed:gain ratio only slightly. Averaged over the two trials, the cumulative feed:gain ratio was almost identical for birds fed mash and pelleted supplements (2.05 vs. 2.04). Some researchers have observed a decline in body weight with no change or a decrease in cumulative feed:gain ratio when feeding mash diets (Proudfoot and Hulan, 1989; Munt et al., 1995; Nir et al., 1995; Leeson et al., 1999), whereas others have observed an increase in feed:gain ratio in addition to reduced growth rate (Proudfoot and Hulan, 1982; Reece et al., 1985; Deaton, 1992; Nir et al., 1994; Hamilton and Proudfoot, 1995). In the present studies, the major impact of feeding a mash supplement was to reduce growth rate, and this reduction might have been responsible for the lower mor-
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1 2 3 4 5 6 Type of supplement Pelleted Mash Level of whole barley × type of supplement 1 × Pellet 1 × Mash 2 × Pellet 2 × Mash 3 × Pellet 3 × Mash 4 × Pellet 4 × Mash 5 × Pellet 5 × Mash 6 × Pellet 6 × Mash SEM P-value Level Supplement Level × supplement
0–7
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BENNETT ET AL. TABLE 9. Cause of mortality from 0 to 49 d in broiler cockerels fed different levels of whole barley and pelleted or mash supplements (Trial 2)
Cause of mortality 1
SDS Ascites and RHF2 Skeletal and leg3 Early4 Infectious Other NVL5 Total
Type of supplement
Level of whole barley6
P-value
1
2
3
4
5
6
Pelleted
Mash
SEM
Level
Supplement
Level × supplement
3.5 0.0 0.5 0.5 0.0 0.5 0.8 6.0
2.2 1.6 0.3 0.0 0.0 0.0 0.5 4.6
4.6 1.1 0.8 0.0 0.0 0.5 0.5 7.6
3.5 0.5 0.3 0.5 0.0 0.5 0.5 6.0
3.3 0.5 0.8 0.0 0.0 0.0 0.0 4.6
2.2 1.4 0.3 0.3 0.3 0.3 0.5 5.2
3.5 1.4a 0.3 0.1 0.0 0.4 0.5 6.1
2.9 0.4b 0.7 0.4 0.1 0.3 0.5 5.3
0.36 0.22 0.18 0.12 0.05 0.13 0.15 0.51
NS NS NS NS NS NS NS NS
NS * NS NS NS NS NS NS
NS NS NS NS NS NS NS NS
a,b
Means with different superscripts are significantly different. SDS = sudden death syndrome. 2 RHF = right heart failure. 3 Skeletal and leg included valgus varus leg deformity, rotated tibia, tibial dyschondroplasia, kinky back; and broken bones. 4 Early included yolk sac infection, dehydration, and starve outs. 5 NVL = No visible lesions. 6 The six levels of whole barley compared were as follows: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. NS P > 0.05. *P < 0.05. 1
In general, feeding whole grain had a less dramatic effect on feed conversion than body weight gain. Cockerels could be fed 5% whole wheat or barley at day of hatch with no loss in feed efficiency. For barley based diets, broilers fed 35% whole grain never displayed an increase in feed:gain ratio compared to birds fed no whole barley (although those fed 20% whole barley had an increased feed:gain ratio at 14 to 28 d). When first introduced to 20, 35, 50, or 65% whole wheat, however, all broilers displayed an increase in feed:gain ratio. By 4 to 7 wk of age, birds on some of the treatments in which 50 to 65% whole barley or 50% whole wheat was fed had the same feed:gain ratio as birds fed the control rations. In terms of feed efficiency, the birds appeared to adjust to whole grain as they grew older. The finding that whole grain had a negative effect on feed efficiency agrees with previous research by Svihus et al. (1997). Researchers who have fed lower amounts of whole grain or introduced it at older ages, however, have found no effect of whole grain on feed conversion (Bennett et al., 1995; Rose et al., 1995, Salah Uddin, 1996). Some of the loss in performance observed when whole grain was fed may be attributed to the absence of insoluble grit from the diets. Grit was excluded in the present trials because it can cause a high level of wear on the equipment used to clean the gizzards at the processing plant. If grit is necessary for the gizzard to grind whole grain efficiently, the absence of grit could have been a problem. McIntosh et al. (1962b) found that grit did not increase the metabolizable energy of whole wheat or barley in two trials and increased the metabolizable energy of ground and whole grain in another trial. Previous research has demonstrated no loss in performance when feeding broiler chickens whole wheat without grit (Bennett et al., 1995). Other research has indicated no benefit to adding grit when feeding whole barley to turkeys (Schwean et al., 1997) and laying
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tality observed due to sudden death syndrome, ascites, and right heart failure. Lower total mortality or mortality due to cardiovascular problems has been found in previous trials when broilers were fed mash rather than pelleted diets (Proudfoot and Hulan, 1982; Proudfoot and Hulan, 1989; Munt et al., 1995; Leeson et al., 1999). Feeding whole wheat or whole barley decreased the growth rate of chickens when combined with mash or pelleted supplements. The youngest birds to exhibit a decreased growth rate were broilers fed 20% whole wheat and a pelleted supplement at 6 to 13 d. Birds fed mashor barley-based supplements were not affected by 20% whole grain. Because mash and barley supplements tended to slow growth, it is possible that the birds were able to process the whole grain fast enough to maintain these growth rates but not the faster rates on the pelleted wheat diets. This finding is consistent with previous research (Svihus et al., 1997) that demonstrated that chickens fed whole barley could grow as fast or faster than birds fed rolled or ground barley. As the amount of whole wheat and whole barley was increased to 35% or more of the diet, some loss in growth rate was observed with both pelleted and mash supplements. Significant interactions of supplement form × whole-grain, however, indicated that the loss was most noticeable with pelleted supplements. Again, it is possible that the bird gizzards could process whole grain fast enough to match the growth rate of birds fed mash diets but not the faster growth rate of birds fed pelleted diets. Previously, researchers have demonstrated that feeding up to 30% whole wheat (Bennett et al., 1995; Salah Uddin et al., 1996) or 60% whole wheat (Rose et al., 1995) would not reduce growth rates compared to pelleted diets. These researchers, however, fed lower amounts of whole wheat or introduced the whole wheat at a later age than in the present trials.
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ACKNOWLEDGMENTS Funding for this research was provided by the Agriculture Development Fund of Saskatchewan Agriculture and Food and Saskatchewan Wheat Pool. The expert technical assistance of Robert Gonda, Karen Schwean, and the Poultry Centre staff is gratefully acknowledged.
REFERENCES Bennett, C. D., H. L. Classen, and C. Riddell. 1995. Live performance and health of broiler chickens fed diets diluted with whole or crumbled wheat. Can. J. Anim. Sci. 75:611–614.
Classen, H. L., and C. Riddell. 1989. Photoperiodic effects on performance and leg abnormalities in broiler chickens. Poult. Sci. 68:873–879. Covasa, M., and J. M. Forbes. 1994. Performance of broiler chickens as affected by split time feeding and wheat-diluted diet. Pages 457–458 in Proceedings 9th European Poultry Conference. Vol. 1. WPSA (United Kingdom Branch), Glasgow, Scotland. Cumming, R. B. 1994. Opportunities in whole grain feeding. Pages 219–222 in Proceedings 9th European Poultry Conference. Vol. 2. WPSA (United Kingdom Branch), Glasgow, Scotland. Deaton, J. W. 1992. The effect of meal feeding on small intestine weight. Poult. Sci. 71:1807–1810. Ferket, P. 2000. Feeding whole grains to poultry improves gut health. Feedstuffs 72(37):12–13,16. Hamilton, R. M. G., and F. G. Proudfoot. 1995. Ingredient particle size and feed texture: Effects on the performance of broiler chickens. Anim. Feed Sci. Technol. 51:203–210. Leeson, S., L. J. Caston, and J. D. Summers. 1999. Performance of male broilers to 70 days when fed diets of varying nutrient density as mash or pellets. J. Appl. Poult. Res. 8:452–464. McIntosh, J. I., S. J. Slinger, I. R. Sibbald, and G. C. Ashton. 1962a. The effects of three physical forms of wheat on the weight gains and feed efficiencies of pullets from hatching to fifteen weeks of age. Poult. Sci. 41:438–444. McIntosh, J. I., S. J. Slinger, I. R. Sibbald, and G. C. Ashton. 1962b. Factors affecting the metabolizable energy content of poultry feeds. 7. The effects of grinding, pelleting and grit feeding on the availability of the energy of wheat, corn, oats and barley. 8. A study of the effects of dietary balance. Poult. Sci. 41:445–456. Munt, R. H. C., J. G. Dingle, and M. G. Sumpa 1995. Growth, carcase composition and profitability of meat chickens given pellets, mash or free-choice diet. Br. Poult. Sci. 36:277–284. Nir, I., R. Hillel, I. Pitchi, and G. Shefet. 1995. Effect of particle size on performance. 3. Grinding pelleting interactions. Poult. Sci. 74:771–783. Nir, I., Y. Twina, E. Grossman, and Z. Nitsan. 1994. Quantitative effects of pelleting on performance, gastrointestinal tract and behaviour of meat-type chickens. Poult. Sci. 35:589–602. Proudfoot, F. G., and H. W. Hulan. 1982. Effects of reduced feeding time using all mash or crumble-pellet dietary regimens on chicken broiler performance, including the incidence of acute death syndrome. Poult. Sci. 61:750–754. Proudfoot, F. G., and H. W. Hulan. 1989. Feed texture effects on the performance of roaster chickens. Can. J. Anim. Sci. 69:801–807. Reece, F. N., B. D. Lott, and J. W. Deaton. 1985. The effects of feed form, grinding method, energy level and gender on broiler performance in a moderate (21 C) environment. Poult. Sci. 64:1834–1839. Rose, S. P., M. Fielden, W. R. Foote, and P. Gardin. 1995. Sequential feeding of whole wheat to growing broiler chickens. Br. Poult. Sci. 36:97–111. Salah Uddin, M., S. P. Rose, T. A. Hiscock, and S. Bonnet. 1996. A comparison of the energy availability for chickens of ground and whole grain samples of two wheat varieties. Br. Poult. Sci. 37:347–357. SAS Institute Inc. 1990. SAS User’s Guide: Statistics. SAS Institute Inc., Cary, NC. Schwean, K., C. D. Bennett, H. L Classen, and C. Riddell. 1997. Influence of whole barley, grit and dawn/dusk lighting on live performance of turkey toms. Can. J. Anim. Sci. 77:558. (Abstr.) Svihus, B., O. Herstad, C. W. Newman, and R. K. Newman. 1997. Comparison of performance and intestinal characteristics of broiler chickens fed on diets containing whole, rolled or ground barley. Br. Poult. Sci. 38:524–529.
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hens (C. D. Bennett, unpublished data). Svihus et al. (1997) fed 70% whole barley to broilers, with and without grit, and observed no effect on body weight, feed conversion, or gizzard weight. Based on previous experience, the absence of insoluble grit does not appear to have had a negative effect. Feeding mash supplement or whole grain did not have a negative effect on carcass yield or the weight of most of the digestive tract organs. Feeding whole grain, however, did cause a significant increase in gizzard weight with progressive increases in gizzard weight from zero to low to high levels of whole grain. Other research has demonstrated that feeding chickens and turkeys whole grain, with or without grit in the diet, will significantly increase gizzard weight (Svihus et al., 1997; C. D. Bennett, unpublished data). The need to increase gizzard weight in response to whole grain may explain the adjustment period observed in growth rate and feed:gain ratio as birds were introduced to higher levels of whole grain. Although the broilers did adapt to high levels of whole wheat and barley, it should be noted that the whole grain was fed without any dilution of the feed. Some popular and scientific reports (Covasa and Forbes, 1994; Ferket, 2000) have indicated that poultry rations can be diluted with whole grain with no loss in performance. It has sometimes been implied that dilution is possible because of some beneficial effect of whole grain compared to mash or pelleted grain. In the present study, no benefit in growth rate or feed conversion was observed in feeding diets containing whole grain. Previous research (Bennett et al., 1995) has demonstrated that dilution with whole grain offers no benefit over dilution with pelleted grain. The results of the present studies indicate that, in the absence of dilution, broiler chickens can be fed up to approximately 35% whole grain in a diet without a great impact on live bird performance. Addition of any amount of whole grain over 5%, however, appears to result in at least a temporary loss in growth or feed efficiency. Producers wanting to add large quantities of whole grain on farm to reduce trucking and milling costs will need to consider the trade-off between lost performance and reduced feed handling costs.
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(Key words: whole wheat, whole barley, mash, pellet, broiler) 2002 Poultry Science 81:995–1003
the energy availability of whole and ground wheat has produced contradictory results, with whole wheat having lower true metabolizable energy but similar apparent metabolizable energy concentration as ground wheat (Salah Uddin et al., 1996). In the present studies, the effect of grain form (whole, mash, or crumbled and pelleted) on growth rate, feed conversion, mortality, and carcass yield of broiler chickens fed wheat and barley based diets was determined. The rate at which whole grain could be increased in the feed as broilers aged was also examined.
INTRODUCTION In the past decade, some poultry producers in Europe, Australia, and Canada have started to add whole wheat on-farm to increase the use of locally grown grains and reduce trucking and feed milling costs (Cumming, 1994). The use of whole grain is not new, however, and early research (McIntosh et al., 1962a) indicated that growing birds could be fed whole grain with little or no loss in performance. More recently, Bennett et al. (1995) and Rose et al. (1995) reported that broiler chickens fed whole-wheat diets had the same market weight and feed conversion as birds fed pelleted wheat diets. Svihus et al. (1997) found in two trials that broiler chickens fed whole barley grew at the same rate but had a higher feed:gain ratio than those fed rolled barley. In a third trial by these researchers, birds fed whole barley gained more weight and had the same feed conversion as birds fed ground barley. Testing of
MATERIALS AND METHODS Trial 1 A total of 2,256 commercial broiler cockerels were housed in four environmentally controlled rooms, with 12 pens per room and 47 chicks in each of the 2.3- × 2-m pens. The birds were reared under an increasing lighting program (Classen and Riddell, 1989). Initial room temperature was 32 C and was then gradually decreased according to usual brooding practices. Hot water pipes provided supplemental heat. All birds received a starter ration from 0 to 13 d of age, a grower ration from 13 to 27 d, and a finisher ration from 27 to 48 d (Table 1). The trial was designed as a 6 × 2 factorial with six combinations of whole grain and two forms of supplement (Table 2). The ingredient composition
2002 Poultry Science Association, Inc. Received for publication October 22, 2001. Accepted for publication January 30, 2002. 1 Trial 1 was previously published as an abstract: Bennett, C. D. and H. L. Classen. 1997. Feeding whole wheat in combination with mash or pelleted supplements. Poult. Sci. 76(Suppl. 1):43. (Abstr.). 2 Present Address: Manitoba Agriculture and Food, 545 University Crescent, Winnipeg, Manitoba, Canada, R3T 5S6. 3 To whom correspondence should be addressed: cbennett@ gov.mb.ca.
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ABSTRACT The effect of grain form (whole, mash, or pelleted) on the live performance of broiler chickens was determined. In the first trial, six regimens compared the feeding of whole wheat: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27d. Each feeding regimen was replicated with steam-pelleted and mash supplements. None of the feed was diluted. The second trial was similar, except that whole barley was fed instead of whole wheat. Feeding
996
BENNETT ET AL. TABLE 1. Dietary treatments–percentages of whole grain in rations (Trials 1 and 2)1 Age (d)
Level of whole grain (wheat in Trial 1, barley in Trial 2)
Trial 1
Trial 2
1
2
3
4
5
6
0–6 6–13 13–27 27–48
0–7 7–14 14–28 28–49
0 0 0 0
0 5 20 35
0 5 35 50
5 20 35 50
0 5 50 65
5 20 50 65
1 Each level of whole-wheat feeding was replicated with the remaining ingredients in the diets being fed in steam-pelleted or mash form. When steam-pelleting was used, the portion of the feed not fed as whole grain was fed as crumbles in the first two periods and as pellets in the last two periods.
the four rooms in the study. For the treatments with steampelleted supplements, the portion of the diet that was not whole grain was fed as a crumble in the starter and grower rations and as a pellet in the finisher ration. After being steam-pelleted, the crumbles or pellets were blended with the whole grain in a ribbon mixer. When mash supplements were used, the grain portion of the supplement was coarsely ground by a hammermill with a 0.64-cm screen. No insoluble grit was fed in any of the treatments. The birds were pen-weighed at 0, 6, 13, 27, and 48 d, and feed consumption was determined for each of these periods. Sixteen birds per treatment, four birds per pen, were selected at 41 d, weighed, fasted overnight, and then killed and processed at 42 d of age to determine carcass yield and weight of internal organs. For the selected birds,
TABLE 2. Percentage ingredient composition and calculated nutritional values of experimental diets in Trials 1 and 2 Trial 1 Ingredient 1
Wheat Barley1 Soybean meal (48% CP) Meat and bone meal Limestone Dicalcium phosphate Canola oil Tallow Salt DL-Methionine Lysine HCL L-Threonine Vitamin-mineral premix2 Feed enzyme3 Ethoxyquin Zinc bacitracin4 Coxistac5 Calculated nutrient content Crude protein, % AME, kcal/kg Methionine + cystine, % Lysine, %
Trial 2
Starter
Grower
Finisher
Starter
Grower
Finisher
55.30 10.00 22.79 5.00 1.05 0.89 1.00 2.79 0.25 0.21 0.20 0.02 0.17 0.10 0.08 0.05 0.10
61.98 15.00 14.00 5.00 1.06 0.92 0.94 0.00 0.25 0.16 0.17 0.03 0.17 0.10 0.08 0.05 0.10
74.25 10.00 8.50 3.50 1.24 1.18 0.30 0.00 0.27 0.08 0.15 0.03 0.17 0.10 0.08 0.05 0.10
39.30 25.00 24.41 5.00 1.02 0.88 3.29 0.00 0.26 0.20 0.14 0.00 0.17 0.10 0.08 0.05 0.10
26.00 50.00 12.68 7.00 0.80 0.62 1.82 0.00 0.24 0.16 0.17 0.02 0.17 0.10 0.08 0.05 0.10
16.44 65.00 8.00 6.92 0.79 0.65 1.30 0.00 0.24 0.06 0.09 0.00 0.17 0.10 0.08 0.05 0.00
22.5 3,000 0.86 1.25
19.8 2,900 0.72 1.00
17.4 2,900 0.58 0.81
22.5 2,950 0.87 1.25
19.0 2,850 0.72 1.00
17.0 2,800 0.58 0.81
1 Depending on the dietary treatment, some of the wheat in Trial 1 and barley in Trial 2 was fed as whole grain. The percentage whole grain in the complete diets for each treatment is displayed in Table 1. 2 The vitamin mineral mix supplied the following per kilogram of complete feed: 11,500 IU vitamin A; 2,600 IU vitamin D3; 40 IU vitamin E; 2.5 mg menadione; 2.5 mg thiamine; 10 mg riboflavin; 84 mg niacin; 4 mg pyridoxine; 0.016 mg vitamin B12; 15.4 mg pantothenic acid; 1.1 mg folic acid; 0.14 mg biotin; 0.125 mg antioxidant; 56 mg iron, 77 mg zinc; 95 mg manganese; 7 mg copper; 0.9 mg iodine; 0.21 mg selenium. 3 Avizyme TX in Trial 1 and Avizyme SX in Trial 2. Both were supplied by Finfeeds International Ltd, Marlborough, Wiltshire, 777 UK. 4 Davis & Lawrence Animal Nutrition, Cambridge, ON, Canada, N3C 2W4. 5 Pfizer Canada Inc., London, ON, Canada, N6A 4C6.
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of the diets was identical for all treatments, with the only difference being in the proportion of the total diet that was fed as whole wheat and whether the portion of the diet that was not whole wheat was fed as ground mash or crumbles and pellets. Six levels of whole wheat were fed: 1) 0% whole wheat from 0 to 48 d; 2) 0% whole wheat at 0 d, 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 0% whole wheat at 0 d, 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% whole wheat at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 0% whole wheat at 0 d, 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% whole wheat at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. Each of the six levels of whole wheat was replicated with steam-pelleted and mash supplements. Each combination of level of whole grain and supplement form was replicated four times with one pen in each of
FEED FORM FOR BROILER CHICKENS
the eviscerated carcass, crop, proventriculus, gizzard (with and without digesta contents), small intestine, and abdominal fat pad were weighed. All birds that died during the trial were weighed and stored at 5 C until postmortem examination. Feed:gain ratio was corrected for mortality by including the weight of the dead birds in the body weight gain.
Trial 2
Statistical Analyses Both trials were analyzed as 6 × 2 factorial designs with level of whole grain and form of supplement as main effects. Statistical analyses were computed with SAS software (1990). When the analysis of variance was significant, Duncan’s multiple-range test was used to separate the means. Differences between treatment means were considered statistically significant at P < 0.05.
RESULTS Trial 1 Birds fed mash supplements had lower body weight gains than those fed pelleted supplements at all ages and cumulatively over the life of the flock (Table 3). Feeding 5% whole wheat from 0 to 6 d had no influence on weight gain. At 6 to 13 d, a significant interaction was observed, and the growth response to feeding of whole wheat depended on the type of supplement used. During this time, the birds fed 20% whole wheat (levels 4 and 6) combined with a pelleted supplement grew slower than birds fed 0 or 5% whole grain and pelleted supplement (levels 1, 2, 3 and 5). Addition of whole wheat to a mash supplement did not slow growth during this period. At 13 to 27 d, a similar interaction occurred; some of the birds fed a pelleted supplement and 35 or 50% whole wheat (levels 4, 5 and 6) gained less weight than birds fed no whole grain
(level 1). Again, no differences due to whole-grain level were observed for the broilers fed mash-based diets. Unlike 6 to 13 d, the birds fed 20% whole grain and a pelleted supplement (level 2) grew at a rate similar to those fed just pellets. From 27 to 48 d, feeding 35 to 65% whole wheat had no effect on body weight gain, regardless of the type of supplement used. Total body weight gain was unaffected by feeding whole wheat. Compared to a pelleted supplement, feeding a mash supplement increased feed:gain ratio from 6 to 27 d, had no effect from 27 to 48 d, and increased cumulative feed:gain ratio (2.06 vs. 2.03; Table 4). At 0 to 27 d, feeding 20% or more whole grain increased feed:gain ratio compared to the rations with no whole grain. At 27 to 48 d, broilers fed 35% whole wheat (level 2) and some of those fed 50% whole wheat (level 4) had similar feed conversions to birds fed no whole wheat (level 1). The birds fed 65% whole wheat in the finisher feed (levels 5 and 6) had a higher feed:gain ratio than birds fed finishers containing 0 or 35% whole wheat (levels 1 and 2). Feed:gain ratio for the life of the flock was lower for birds reared on the control rations (level 1) than any of the birds reared on whole-grain diets. Broilers fed the highest two levels of whole wheat had a higher cumulative feed:gain ratio than most of the other treatments in which whole grain was used (level 5 vs. levels 2 to 4; level 6 vs. levels 2 and 4). Feeding a mash supplement reduced mortality due to sudden death syndrome and increased skeletal and leg problems but did not change total mortality compared to feeding a pelleted supplement (Table 5). Feeding almost any amount of whole wheat (levels 2, 3, 4, and 6) reduced skeletal and leg problems compared to not feeding any whole grain but did not change total mortality. Sudden death syndrome and skeletal and leg problems accounted for approximately two-thirds of the mortality in the trial. Feeding mash supplements compared to pelleted supplements resulted in a small but significant increase in the weight of the gizzard, with and without digesta contents, as a percentage of the live weight of the bird (Table 6). Eviscerated carcass yield and the percentage weight of other organs were unaffected by feeding mash supplements. Feeding some levels of whole wheat (levels 3, 4, and 5) increased the percentage of offal compared to not feeding any whole wheat but did not alter eviscerated carcass yield. Feeding whole wheat had no overall effect on percentage proventriculus, but a significant interation of whole-wheat level × supplement form did occur, and some inconsistent differences were observed (data not shown). For birds fed pelleted supplements, birds fed the sixth level of whole wheat had larger proventriculi than those fed the third, fourth, or fifth levels of whole wheat. When mash supplements were used, birds fed the fourth level of whole wheat had larger proventriculi than those fed the second level of whole wheat. Crop, small intestine, and abdominal fat pad weights were unaffected by wholegrain level or form of supplement. The most noticeable dietary effects on organ weight were observed in the response of gizzard weight to different levels of whole grain. Cockerels fed no whole wheat had
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A total of 2,208 commercial broiler cockerels was housed and reared similarly to Trial 1, except that 46 instead of 47 chicks were placed per pen. All birds received barleybased starter ration from 0 to 14 d of age, grower ration from 14 to 28 d, and finisher ration from 28 to 49 d (Table 1). As in the previous trial, Trial 2 was designed as a 6 × 2 factorial with six levels of whole grain and two forms of supplement (Table 2). The same six whole-grain feeding regimens were used as in Trial 1, except that whole barley was fed instead of whole wheat and the whole-grain levels were changed at 1 d of age later than Trial 1. The steampelleted and mash supplements were produced in a manner and form similar to Trial 1. No insoluble grit was fed. The birds were pen weighed at 0, 7, 14, 28, and 49 d of age, and feed consumption was determined for each of these time periods. All birds that died during the trial were weighed and stored at 5 C until postmortem examination. The feed:gain ratio was corrected for mortality by including the weight of the dead birds in the body weight gain.
997
998
BENNETT ET AL. TABLE 3. Body weight gain (g) of broiler cockerels fed different levels of whole wheat and pelleted or mash supplements (Trial 1) Age (d) 1
Level of whole wheat
0–6
a
13–27
27–48
0–48
102 104 104 103 105 99
235 238a 234a 224bc 232ab 224c
904 894 893 899 901 894
1,641 1,618 1,598 1,609 1,593 1,587
2,882 2,853 2,829 2,838 2,831 2,804
108a 98b
240a 223b
933a 862b
1,628a 1,588b
2,909a 2,770b
108 97 107 101 111 97 106 100 110 101 103 96 1.1
244a 226c 252a 224c 249a 220c 231bc 222c 241ab 223c 227c 222c 1.8
957a 852c 934ab 854c 934ab 852c 931b 868c 927b 875c 918b 869c 5.8
1,670 1,613 1,644 1,591 1,614 1,583 1,644 1,574 1,616 1,570 1,577 1,596 8.1
2,978 2,788 2,937 2,769 2,908 2,751 2,912 2,764 2,893 2,769 2,825 2,783 13.8
NS *** NS
*** *** **
NS *** **
NS * NS
NS *** NS
a–c
Means with different superscripts are significantly different. The six levels of whole wheat compared were as follows: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. NS P > 0.05. *P < 0.05. **P < 0.01. ***P < 0.001. 1
TABLE 4. Feed:gain of broiler cockerels fed different levels of whole wheat and pelleted or mash supplements (Trial 1) Age (d) 1
Level of whole wheat 1 2 3 4 5 6 Type of supplement Pelleted Mash SEM P-value Level Supplement Level × supplement a–d
0–6
6–13
13–27
1.251 1.203 1.211 1.215 1.198 1.235
c
1.321 1.325bc 1.341abc 1.378a 1.344abc 1.364ab
c
27–48
1.620 1.666ab 1.673ab 1.654b 1.694a 1.694a
2.366 2.407bc 2.446ab 2.427abc 2.482a 2.485a
1.991d 2.025c 2.050bc 2.038c 2.073ab 2.082a
1.215 1.223 0.0092
1.331b 1.359a 0.0065
1.630b 1.704a 0.0077
2.446 2.425 0.0107
2.028b 2.058a 0.0061
NS NS NS
* * NS
*** *** NS
** NS NS
*** ** NS
c
0–48
Means with different superscripts are significantly different. The six levels of whole wheat compared were as follows: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. NS P > 0.05. *P < 0.05. **P < 0.01. ***P < 0.001. 1
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1 2 3 4 5 6 Type of supplement Pelleted Mash Level of whole wheat × type of supplement 1 × Pellet 1 × Mash 2 × Pelleted 2 × Mash 3 × Pelleted 3 × Mash 4 × Pelleted 4 × Mash 5 × Pelleted 5 × Mash 6 × Pelleted 6 × Mash SEM P-value Level Supplement Level × supplement
6–13
999
FEED FORM FOR BROILER CHICKENS TABLE 5. Cause of mortality from 0 to 48 d of broiler cockerels fed different levels of whole wheat and pelleted or mash supplements (Trial 1) Type of supplement
Level of whole wheat6
P-value
Cause of mortality
1
2
3
4
5
6
Pelleted
Mash
SEM
Level
Supplement
Level × supplement
SDS1 Ascites and RHF2 Skeletal and leg3 Early mortality4 Infectious Other NVL5 Total
3.99 1.06 3.19a 0.00 0.00 0.27 0.53 9.04
4.52 0.53 1.06b 1.33 0.53 0.80 0.00 8.78
4.52 0.53 0.53b 0.27 0.00 0.80 0.80 7.45
3.46 0.53 1.06b 0.53 0.00 0.53 0.53 6.65
2.39 1.33 2.39ab 1.06 0.53 0.53 0.80 9.04
1.86 1.86 1.06b 1.33 0.00 0.53 0.00 6.65
4.08a 1.33 0.98b 0.62 0.09 0.71 0.71 8.51
2.84b 0.62 2.13a 0.89 0.27 0.44 0.18 7.36
0.345 0.228 0.281 0.205 0.107 0.176 0.167 0.693
NS NS * NS NS NS NS NS
* NS * NS NS NS NS NS
NS NS NS NS NS NS NS NS
Means with different superscripts are significantly different; P < 0.05. SDS = Sudden death syndrome. 2 RHF = Right heart failure. 3 Skeletal and leg included valgus varus leg deformity, rotated tibia, tibial dyschondroplasia, kinky back, and broken bones. 4 Early mortality included yolk sac infection, dehydration, and starve outs. 5 NVL = No visible lesions. 6 The six levels of whole wheat compared were as follows: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. NS P > 0.05. *P < 0.05. a,b 1
birds fed the fourth level of whole wheat). A significant interaction indicated that type of supplement influenced the effect of whole grain on gizzard weight, with and without digest (data not displayed). For pelleted supplements, the control birds had smaller gizzards than birds
TABLE 6. Dressed and eviscerated carcass yields and relative organ weights at 41 d of broiler cockerels fed different levels of whole wheat and pelleted or mash supplements (Trial 1) Carcass/organ weight (% of live bird weight)
Level of whole wheat4 1 2 3 4 5 6 Type of supplement Pelleted Mash SEM P-value Level Supplement Level × supplement a–c
Dressed carcass1
Eviscerated carcass2
Offal3
Crop
Proventriculus
Gizzard
Gizzard + digesta
Small intestine
Abdominal fat pad
78.27 78.10 78.48 78.66 78.33 78.87
65.71 65.14 65.04 65.62 64.99 65.52
12.56b 12.94ab 13.44a 13.04ab 13.34a 13.35a
0.26 0.26 0.25 0.26 0.27 0.26
0.33 0.33 0.34 0.35 0.34 0.36
1.37c 1.62b 1.88a 1.76a 1.87a 1.83a
1.55c 1.93b 2.18a 2.05ab 2.17a 2.13a
2.06 2.03 2.15 2.06 2.10 2.03
1.64 1.70 1.80 1.66 1.76 1.69
78.44 78.47 0.104
65.46 65.21 0.121
12.97b 13.26a 0.072
0.26 0.26 0.003
0.34 0.34 0.004
1.67b 1.78a 0.021
1.91b 2.11a 0.026
2.01 2.10 0.017
1.73 1.69 0.033
NS NS NS
NS NS NS
** * NS
NS NS NS
NS NS **
*** *** *
*** *** **
NS NS NS
NS NS NS
Means with different superscripts are significantly different. Dressed carcass = carcass with feathers, head, neck and feet removed. 2 Eviscerated carcass = dressed carcass with viscera removed. 3 Offal = dressed carcass − eviscerated carcass weight. 4 The six levels of whole wheat compared were as follows: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. NS P > 0.05. *P < 0.05. **P < 0.01. ***P < 0.001. 1
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smaller gizzards, with or without digesta, than those of birds fed any whole wheat. Birds fed a low amount of whole wheat (level 2) had full and empty gizzard weights lower than almost all of the birds fed higher levels of whole wheat (except compared to the empty gizzard weight of
1000
BENNETT ET AL. TABLE 7. Body weight gain (g) of broiler cockerels fed different levels of whole barley and pelleted or mash supplements (Trial 2) Age (d) 0–7
7–14
14–28
28–49
0–49
79a 72c 71c 78ab 73bc 78ab
207 204 204 204 203 205
831 817 825 828 823 836
1,670a 1,593b 1,618b 1,591b 1,607b 1,610b
2,787a 2,686b 2,718b 2,702b 2,706b 2,729ab
79a 71b
211a 198b
852a 802b
1,634a 1,596b
2,776a 2,667b
85a 72b 74b 69b 71b 71b 86a 71b 74b 73b 85a 72b 1.0
212 202 211 198 206 202 215 194 208 198 216 195 1.3
866a 796e 848ab 787e 840abc 810de 861a 795e 830bcd 816cde 864a 807de 4.6
1,709 1,632 1,611 1,575 1,646 1,590 1,621 1,562 1,607 1,607 1,606 1,614 7.8
2,872 2,702 2,744 2,682 2,764 2,672 2,783 2,622 2,720 2,693 2,771 2,688 12.5
*** *** *
NS *** NS
NS *** *
* ** NS
* *** NS
1
a–e
Means with different superscripts are significantly different. The six levels of whole barley compared were as follows: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. NS P > 0.05. *P < 0.05. **P < 0.01. ***P < 0.001. 1
fed any whole wheat (levels 2 to 6). For mash supplements, the control birds had gizzard weights similar to birds fed the least whole wheat (level 2). Some other inconsistent differences were observed among the different types of supplement, but the basic trend was for gizzard weight to increase as more whole grain was fed. Numerically, the differences in gizzard weight accounted for most of the differences in eviscerated carcass yield among the birds fed different levels of whole grain.
Trial 2 As in Trial 1, feeding a mash supplement decreased body weight gain in all periods and reduced total body weight gain compared to a pelleted supplement (Table 7). Feeding whole barley decreased body weight gain overall and during many periods. From 0 to 7 d, however, the response to whole barley appeared to be positive and the broilers fed 5% whole barley plus a pelleted supplement (levels 4 and 6) had a greater weight gain than some of the birds fed no whole barley at that age (levels 2, 3, and 5). A significant interaction indicated that this improvement only occurred for birds fed pelleted supplements. At 7 to 14 d, feeding whole barley had no effect on weight gain
even though some of the birds were fed 20% whole grain during this time. From 14 to 28 d, feeding whole barley had no overall effect on weight gain but a significant interaction was observed. The birds fed a pelleted supplement and 50% whole barley (level 5) had a lower body weight gain than the other birds fed pelleted supplements, but no significant differences were observed when whole barley was added to mash supplements. From 28 to 49 d of age, all of the birds, even those fed 35% whole barley, grew slower than those fed the control diets, and no influence of supplement form on this reduction in growth rate was observed. Compared to the birds on the control diets (level 1), total body weights gain were reduced for all birds fed whole barley, except for those fed the maximum level of whole barley (level 6). Feed:gain ratio was similar at all ages and in total for birds fed mash and pelleted supplements (Table 8). Feeding 5% whole barley from 0 to 7 d (levels 4 and 6) improved feed conversion compared to several of the treatments in which no whole grain was fed (levels 2, 3, and 5); this pattern was similar to the one observed for body weight gain at the same age. From 7 to 14 d, feeding whole barley had no impact on feed conversion, but at 14 to 28 d of age most of the birds fed whole barley (levels 2, 4, 5, and 6)
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Level of whole barley 1 2 3 4 5 6 Type of supplement Pelleted Mash Level of whole barley × type of supplement 1 × Pelleted 1 × Mash 2 × Pelleted 2 × Mash 3 × Pelleted 3 × Mash 4 × Pelleted 4 × Mash 5 × Pelleted 5 × Mash 6 × Pelleted 6 × Mash SEM P-value Level Supplement Level × supplement
1001
FEED FORM FOR BROILER CHICKENS TABLE 8. Feed:gain ratio of broiler cockerels fed different levels of whole barley and pelleted or mash supplements (Trial 2) Age (d) 1
Level of whole barley
7–14
14–28
1.283 1.457a 1.398ab 1.277c 1.394ab 1.329bc
1.249 1.281 1.280 1.289 1.285 1.293
c
1.635 1.661ab 1.651bc 1.665ab 1.674a 1.675a
2.327 2.360bc 2.384ab 2.408a 2.385ab 2.387ab
2.004b 2.037a 2.044a 2.056a 2.053a 2.050a
1.349 1.364
1.284 1.275
1.661 1.659
2.385 2.365
2.042 2.039
1.250 1.317 1.485 1.430 1.416 1.379 1.238 1.316 1.411 1.377 1.294 1.364 0.0157
1.259 1.239 1.257 1.306 1.292 1.268 1.311 1.268 1.274 1.295 1.310 1.276 0.0058
1.618 1.651 1.662 1.660 1.648 1.654 1.669 1.660 1.682 1.667 1.687 1.663 0.0034
2.325d 2.328cd 2.365bcd 2.356bcd 2.385abcd 2.383abcd 2.399abc 2.418ab 2.394abcd 2.376abcd 2.445a 2.329cd 0.0075
1.994d 2.015cd 2.032bcd 2.041abc 2.045abc 2.044abc 2.046abc 2.066ab 2.056abc 2.050abc 2.080a 2.021cd 0.0047
** NS NS
NS NS NS
** NS NS
* NS *
** NS *
c
28–49 c
0–49
a–d
Means with different superscripts are significantly different. The six levels of whole barley compared were as follows: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. NS P > 0.05. *P < 0.05. **P < 0.01. ***P < 0.001. 1
had a higher feed:gain ratio than the birds on the control rations. Use of whole-barley diets improved by 28 to 49 d, and the improvement in feed efficiency was most noticeable with mash supplements (significant interaction of whole-grain level × supplement form). At this age, most of the birds fed mash supplements had a similar feed:gain ratio (levels 1, 2, 3, 5, and 6). For pelleted supplements, the birds fed no whole barley had a lower feed:gain ratio than some of the birds fed high amounts of whole barley (levels 4 and 6), and the birds fed a low amount of whole barley (level 2) had a lower feed:gain ratio than birds fed the most whole barley (level 6). The effect of feeding whole barley on cumulative feed:gain ratio was similar to that observed at 28 to 49 d, and a significant interaction occurred between supplement form and level of whole grain. For broilers fed mash supplements, most of the birds had cumulative feed conversions that were similar (levels 1, 2, 3, 5, and 6). When pelleted supplements were used, the birds fed the control rations had a feed:gain ratio lower than birds fed high amounts of whole grain (levels 3 to 6). Chickens fed a low amount of whole barley and pelleted supplement (level 2) had a lower feed:gain ratio than birds fed the highest level of whole grain (level 6). Mortality due to ascites and right heart failure was reduced by feeding a mash supplement, but total mortality
was unaffected (Table 9). Feeding whole barley did not affect cause of mortality or total mortality. As in Trial 1, approximately two-thirds of the mortality was due to sudden death syndrome and skeletal and leg problems.
DISCUSSION Compared to a pelleted supplement, feeding a wheat or barley mash supplement slowed growth rate at all ages but had almost no effect on feed efficiency. Barley mash supplements had no effect on cumulative feed:gain ratio, and wheat mash supplements increased feed:gain ratio only slightly. Averaged over the two trials, the cumulative feed:gain ratio was almost identical for birds fed mash and pelleted supplements (2.05 vs. 2.04). Some researchers have observed a decline in body weight with no change or a decrease in cumulative feed:gain ratio when feeding mash diets (Proudfoot and Hulan, 1989; Munt et al., 1995; Nir et al., 1995; Leeson et al., 1999), whereas others have observed an increase in feed:gain ratio in addition to reduced growth rate (Proudfoot and Hulan, 1982; Reece et al., 1985; Deaton, 1992; Nir et al., 1994; Hamilton and Proudfoot, 1995). In the present studies, the major impact of feeding a mash supplement was to reduce growth rate, and this reduction might have been responsible for the lower mor-
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1 2 3 4 5 6 Type of supplement Pelleted Mash Level of whole barley × type of supplement 1 × Pellet 1 × Mash 2 × Pellet 2 × Mash 3 × Pellet 3 × Mash 4 × Pellet 4 × Mash 5 × Pellet 5 × Mash 6 × Pellet 6 × Mash SEM P-value Level Supplement Level × supplement
0–7
1002
BENNETT ET AL. TABLE 9. Cause of mortality from 0 to 49 d in broiler cockerels fed different levels of whole barley and pelleted or mash supplements (Trial 2)
Cause of mortality 1
SDS Ascites and RHF2 Skeletal and leg3 Early4 Infectious Other NVL5 Total
Type of supplement
Level of whole barley6
P-value
1
2
3
4
5
6
Pelleted
Mash
SEM
Level
Supplement
Level × supplement
3.5 0.0 0.5 0.5 0.0 0.5 0.8 6.0
2.2 1.6 0.3 0.0 0.0 0.0 0.5 4.6
4.6 1.1 0.8 0.0 0.0 0.5 0.5 7.6
3.5 0.5 0.3 0.5 0.0 0.5 0.5 6.0
3.3 0.5 0.8 0.0 0.0 0.0 0.0 4.6
2.2 1.4 0.3 0.3 0.3 0.3 0.5 5.2
3.5 1.4a 0.3 0.1 0.0 0.4 0.5 6.1
2.9 0.4b 0.7 0.4 0.1 0.3 0.5 5.3
0.36 0.22 0.18 0.12 0.05 0.13 0.15 0.51
NS NS NS NS NS NS NS NS
NS * NS NS NS NS NS NS
NS NS NS NS NS NS NS NS
a,b
Means with different superscripts are significantly different. SDS = sudden death syndrome. 2 RHF = right heart failure. 3 Skeletal and leg included valgus varus leg deformity, rotated tibia, tibial dyschondroplasia, kinky back; and broken bones. 4 Early included yolk sac infection, dehydration, and starve outs. 5 NVL = No visible lesions. 6 The six levels of whole barley compared were as follows: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27 d. NS P > 0.05. *P < 0.05. 1
In general, feeding whole grain had a less dramatic effect on feed conversion than body weight gain. Cockerels could be fed 5% whole wheat or barley at day of hatch with no loss in feed efficiency. For barley based diets, broilers fed 35% whole grain never displayed an increase in feed:gain ratio compared to birds fed no whole barley (although those fed 20% whole barley had an increased feed:gain ratio at 14 to 28 d). When first introduced to 20, 35, 50, or 65% whole wheat, however, all broilers displayed an increase in feed:gain ratio. By 4 to 7 wk of age, birds on some of the treatments in which 50 to 65% whole barley or 50% whole wheat was fed had the same feed:gain ratio as birds fed the control rations. In terms of feed efficiency, the birds appeared to adjust to whole grain as they grew older. The finding that whole grain had a negative effect on feed efficiency agrees with previous research by Svihus et al. (1997). Researchers who have fed lower amounts of whole grain or introduced it at older ages, however, have found no effect of whole grain on feed conversion (Bennett et al., 1995; Rose et al., 1995, Salah Uddin, 1996). Some of the loss in performance observed when whole grain was fed may be attributed to the absence of insoluble grit from the diets. Grit was excluded in the present trials because it can cause a high level of wear on the equipment used to clean the gizzards at the processing plant. If grit is necessary for the gizzard to grind whole grain efficiently, the absence of grit could have been a problem. McIntosh et al. (1962b) found that grit did not increase the metabolizable energy of whole wheat or barley in two trials and increased the metabolizable energy of ground and whole grain in another trial. Previous research has demonstrated no loss in performance when feeding broiler chickens whole wheat without grit (Bennett et al., 1995). Other research has indicated no benefit to adding grit when feeding whole barley to turkeys (Schwean et al., 1997) and laying
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tality observed due to sudden death syndrome, ascites, and right heart failure. Lower total mortality or mortality due to cardiovascular problems has been found in previous trials when broilers were fed mash rather than pelleted diets (Proudfoot and Hulan, 1982; Proudfoot and Hulan, 1989; Munt et al., 1995; Leeson et al., 1999). Feeding whole wheat or whole barley decreased the growth rate of chickens when combined with mash or pelleted supplements. The youngest birds to exhibit a decreased growth rate were broilers fed 20% whole wheat and a pelleted supplement at 6 to 13 d. Birds fed mashor barley-based supplements were not affected by 20% whole grain. Because mash and barley supplements tended to slow growth, it is possible that the birds were able to process the whole grain fast enough to maintain these growth rates but not the faster rates on the pelleted wheat diets. This finding is consistent with previous research (Svihus et al., 1997) that demonstrated that chickens fed whole barley could grow as fast or faster than birds fed rolled or ground barley. As the amount of whole wheat and whole barley was increased to 35% or more of the diet, some loss in growth rate was observed with both pelleted and mash supplements. Significant interactions of supplement form × whole-grain, however, indicated that the loss was most noticeable with pelleted supplements. Again, it is possible that the bird gizzards could process whole grain fast enough to match the growth rate of birds fed mash diets but not the faster growth rate of birds fed pelleted diets. Previously, researchers have demonstrated that feeding up to 30% whole wheat (Bennett et al., 1995; Salah Uddin et al., 1996) or 60% whole wheat (Rose et al., 1995) would not reduce growth rates compared to pelleted diets. These researchers, however, fed lower amounts of whole wheat or introduced the whole wheat at a later age than in the present trials.
FEED FORM FOR BROILER CHICKENS
ACKNOWLEDGMENTS Funding for this research was provided by the Agriculture Development Fund of Saskatchewan Agriculture and Food and Saskatchewan Wheat Pool. The expert technical assistance of Robert Gonda, Karen Schwean, and the Poultry Centre staff is gratefully acknowledged.
REFERENCES Bennett, C. D., H. L. Classen, and C. Riddell. 1995. Live performance and health of broiler chickens fed diets diluted with whole or crumbled wheat. Can. J. Anim. Sci. 75:611–614.
Classen, H. L., and C. Riddell. 1989. Photoperiodic effects on performance and leg abnormalities in broiler chickens. Poult. Sci. 68:873–879. Covasa, M., and J. M. Forbes. 1994. Performance of broiler chickens as affected by split time feeding and wheat-diluted diet. Pages 457–458 in Proceedings 9th European Poultry Conference. Vol. 1. WPSA (United Kingdom Branch), Glasgow, Scotland. Cumming, R. B. 1994. Opportunities in whole grain feeding. Pages 219–222 in Proceedings 9th European Poultry Conference. Vol. 2. WPSA (United Kingdom Branch), Glasgow, Scotland. Deaton, J. W. 1992. The effect of meal feeding on small intestine weight. Poult. Sci. 71:1807–1810. Ferket, P. 2000. Feeding whole grains to poultry improves gut health. Feedstuffs 72(37):12–13,16. Hamilton, R. M. G., and F. G. Proudfoot. 1995. Ingredient particle size and feed texture: Effects on the performance of broiler chickens. Anim. Feed Sci. Technol. 51:203–210. Leeson, S., L. J. Caston, and J. D. Summers. 1999. Performance of male broilers to 70 days when fed diets of varying nutrient density as mash or pellets. J. Appl. Poult. Res. 8:452–464. McIntosh, J. I., S. J. Slinger, I. R. Sibbald, and G. C. Ashton. 1962a. The effects of three physical forms of wheat on the weight gains and feed efficiencies of pullets from hatching to fifteen weeks of age. Poult. Sci. 41:438–444. McIntosh, J. I., S. J. Slinger, I. R. Sibbald, and G. C. Ashton. 1962b. Factors affecting the metabolizable energy content of poultry feeds. 7. The effects of grinding, pelleting and grit feeding on the availability of the energy of wheat, corn, oats and barley. 8. A study of the effects of dietary balance. Poult. Sci. 41:445–456. Munt, R. H. C., J. G. Dingle, and M. G. Sumpa 1995. Growth, carcase composition and profitability of meat chickens given pellets, mash or free-choice diet. Br. Poult. Sci. 36:277–284. Nir, I., R. Hillel, I. Pitchi, and G. Shefet. 1995. Effect of particle size on performance. 3. Grinding pelleting interactions. Poult. Sci. 74:771–783. Nir, I., Y. Twina, E. Grossman, and Z. Nitsan. 1994. Quantitative effects of pelleting on performance, gastrointestinal tract and behaviour of meat-type chickens. Poult. Sci. 35:589–602. Proudfoot, F. G., and H. W. Hulan. 1982. Effects of reduced feeding time using all mash or crumble-pellet dietary regimens on chicken broiler performance, including the incidence of acute death syndrome. Poult. Sci. 61:750–754. Proudfoot, F. G., and H. W. Hulan. 1989. Feed texture effects on the performance of roaster chickens. Can. J. Anim. Sci. 69:801–807. Reece, F. N., B. D. Lott, and J. W. Deaton. 1985. The effects of feed form, grinding method, energy level and gender on broiler performance in a moderate (21 C) environment. Poult. Sci. 64:1834–1839. Rose, S. P., M. Fielden, W. R. Foote, and P. Gardin. 1995. Sequential feeding of whole wheat to growing broiler chickens. Br. Poult. Sci. 36:97–111. Salah Uddin, M., S. P. Rose, T. A. Hiscock, and S. Bonnet. 1996. A comparison of the energy availability for chickens of ground and whole grain samples of two wheat varieties. Br. Poult. Sci. 37:347–357. SAS Institute Inc. 1990. SAS User’s Guide: Statistics. SAS Institute Inc., Cary, NC. Schwean, K., C. D. Bennett, H. L Classen, and C. Riddell. 1997. Influence of whole barley, grit and dawn/dusk lighting on live performance of turkey toms. Can. J. Anim. Sci. 77:558. (Abstr.) Svihus, B., O. Herstad, C. W. Newman, and R. K. Newman. 1997. Comparison of performance and intestinal characteristics of broiler chickens fed on diets containing whole, rolled or ground barley. Br. Poult. Sci. 38:524–529.
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hens (C. D. Bennett, unpublished data). Svihus et al. (1997) fed 70% whole barley to broilers, with and without grit, and observed no effect on body weight, feed conversion, or gizzard weight. Based on previous experience, the absence of insoluble grit does not appear to have had a negative effect. Feeding mash supplement or whole grain did not have a negative effect on carcass yield or the weight of most of the digestive tract organs. Feeding whole grain, however, did cause a significant increase in gizzard weight with progressive increases in gizzard weight from zero to low to high levels of whole grain. Other research has demonstrated that feeding chickens and turkeys whole grain, with or without grit in the diet, will significantly increase gizzard weight (Svihus et al., 1997; C. D. Bennett, unpublished data). The need to increase gizzard weight in response to whole grain may explain the adjustment period observed in growth rate and feed:gain ratio as birds were introduced to higher levels of whole grain. Although the broilers did adapt to high levels of whole wheat and barley, it should be noted that the whole grain was fed without any dilution of the feed. Some popular and scientific reports (Covasa and Forbes, 1994; Ferket, 2000) have indicated that poultry rations can be diluted with whole grain with no loss in performance. It has sometimes been implied that dilution is possible because of some beneficial effect of whole grain compared to mash or pelleted grain. In the present study, no benefit in growth rate or feed conversion was observed in feeding diets containing whole grain. Previous research (Bennett et al., 1995) has demonstrated that dilution with whole grain offers no benefit over dilution with pelleted grain. The results of the present studies indicate that, in the absence of dilution, broiler chickens can be fed up to approximately 35% whole grain in a diet without a great impact on live bird performance. Addition of any amount of whole grain over 5%, however, appears to result in at least a temporary loss in growth or feed efficiency. Producers wanting to add large quantities of whole grain on farm to reduce trucking and milling costs will need to consider the trade-off between lost performance and reduced feed handling costs.
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