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Influence of Dietary Fat on Economic Returns of Commercial Leghorns
2003 Poultry Science Association, Inc.
Influence of Dietary Fat on Economic Returns of Commercial Leghorns S. S. Sohail, M. M. Bryant, and D. A. Roland, Sr.1 Department of Poultry Science and Alabama Agricultural Experiment Station, Auburn University, Alabama 36849
Primary Audience: Nutritionists, Feed Manufacturers, Egg Producers SUMMARY The beneficial effect of dietary fat and protein on improving egg weight (EW) is well-documented. However, many egg producers do not supplement fat in commercial hen diets because of inadequate storing and mixing facilities. To improve egg size without using fat, higher protein levels are fed. However, dietary protein has a greater heat increment than fat that could adversely affect hen performance during summer. The maximum dietary protein level that can be economically fed with no added fat without having an adverse effect on hen performance during summer or heat stress is not known. A study was conducted under summer conditions to determine the maximum dietary protein level that could be economically fed without using fat and if money is lost by not using dietary fat during summer. Supplementing fat increased EW and BW of hens in the study. Increasing dietary protein had a positive linear effect on EW. Neither fat nor protein had an effect on egg production, egg mass, or egg specific gravity. Fat increased FC and feed efficiency at the two higher protein levels (19.8 and 18.7%) but not at the lower level (17.4%). Economics of using fat indicated that egg producers feeding diets without fat are losing approximately 1.4 to 3.1 cents per dozen eggs depending upon fat cost and the spread in price between medium and large eggs. Key words: egg weight, fat, Leghorn, profit, protein 2003 J. Appl. Poult. Res. 12:356–361
DESCRIPTION OF PROBLEM The effect of fat and protein on increasing egg weight (EW) of commercial Leghorns has been well-documented [1, 2, 3]. Many egg producers, however, do not use supplemental fat because of inadequate storing and mixing facilities, and they rely instead on protein to maximize egg size. Dietary protein has a greater heat increment than fat, adversely affecting hen performance during periods of high environmental temperatures [4]. There is concern about how high dietary protein levels can be during the summer or periods of heat stress. A review of 1
the literature indicated that the optimal dietary protein level that can be economically fed with no added fat without having an adverse effect on hen performance is not known. There is also insufficient data to allow producers to calculate the cost of not using fat in commercial Leghorn diets at different fat and egg prices. This research was conducted to compare 1) the influence of varying protein levels with or without fat on EW, egg production (EP), and feed consumption (FC) during summer, and 2) to gather data required for egg producers to calculate if it is economical to invest in equipment necessary to add fat.
To whom correspondence should be addressed: [email protected].
SOHAIL ET AL.: DIETARY FAT AND ECONOMIC GAIN
357
TABLE 1. Ingredients and nutrient composition of experimental diets Experimental diets Ingredient
1
2
3
4
5
6
(%) A
Corn 8.6% Soybean meal 48%A LimestoneB Hard shellB Dicalcium phosphateC Poultry oilD NaCl Vitamin premixE Mineral premixF G DL-Methionine NatuphosH Cost ($/ton) Calculated analysis ME, kcal/kg per lb CP, % Calcium,I % Total P, I % NPP,I % Sodium, % Methionine, % Methionine + cystine, % Lysine, % Tryptophan, % Chloride, % Threonine, %
51.74 31.92 7.91 2.00 1.16 4.24 0.39 0.25 0.25 0.13 0.05 146.29
56.92 30.99 7.92 2.00 1.15 0.00 0.39 0.25 0.25 0.13 0.05 137.97
55.24 28.98 7.92 2.00 1.18 3.65 0.39 0.25 0.25 0.14 0.05 141.57
59.70 28.18 7.93 2.00 1.17 0.00 0.33 0.25 0.25 0.14 0.05 134.41
60.86 25.20 7.93 2.00 1.19 1.75 0.39 0.25 0.25 0.17 0.05 134.08
62.90 25.02 8.05 2.00 0.97 0.00 0.39 0.25 0.25 0.17 0.05 130.44
1,305 19.77 4.25 0.55 0.32 0.18 0.46 0.77 1.10 0.25 0.26 0.75
1,217 19.77 4.25 0.55 0.32 0.18 0.46 0.77 1.09 0.25 0.27 0.74
1,305 18.66 4.25 0.54 0.32 0.18 0.45 0.75 1.02 0.23 0.27 0.70
1,229 18.66 4.25 0.54 0.32 0.18 0.45 0.75 1.01 0.23 0.27 0.70
1,280 17.33 4.25 0.53 0.32 0.18 0.47 0.74 0.92 0.21 0.27 0.64
1,243 17.41 4.25 0.53 0.32 0.18 0.47 0.74 0.92 0.21 0.27 0.65
A
Amino acid content of corn and soybean meal was determined by ion exchange chromatography. Calcium carbonate was supplied as limestone (16 × 120 U.S. mesh, 1.9 to 0.125 mm) and hardshell (4 × 8 U.S. mesh, 4.75 to 2.36 mm). C Dynafos; IMC-Agrico Feed Ingredients, Bannockburn, IL 60015. D Price of poultry oil was $12.75 per 100 lb. E Provided per kilogram of diet: vitamin A (as retinyl acetate), 8,000 IU; cholecalciferol, 2,200 ICU; vitamin E (as dl-alpha tocopheryl acetate), 8 IU; vitamin B12, 0.02 mg; riboflavin, 5.5 mg; D-calcium pantothenic acid, 13 mg; niacin, 36 mg; choline, 500 mg; folic acid, 0.5 mg; vitamin B1 (thiamin mononitrate), 1 mg; pyridoxine, 2.2 mg; d-biotin, 0.05 mg; vitamin K (menadione sodium bisulfite complex), 2 mg. F Provided per kilogram of diet: manganous oxide, 65 mg; iodine (ethylene diamine dihydriodide), 1 mg; ferrous carbonate, 55 mg; copper oxide, 6 mg; zinc oxide, 55 mg; sodium selenite, 0.3 mg. G Degussa Corporation, Ridgefield Park, NJ. H Natuphos contained 600-phytase units/g, BASF Corp., Mt. Olive, NJ. I Dietary Ca, total P, and NPP (nonphytate P) values were determined by chemical analysis and values adjusted for feed formulation. B
MATERIALS AND METHODS This experiment was conducted as a randomized block design with two fat (without and with fat) and three protein levels (17.4, 18.7, and 19.8%) using 21-wk-old Hy-Line W36 hens [5; Table 1]. The diet containing 17.4% protein is a commercial layer diet used during the winter, which was formulated based on lysine [6]. Diets containing 18.7 and 19.8% protein were formulated based on protein [6] and are used during summer or periods of heat stress. Poultry oil was
used as the source of fat to increase dietary energy (Table 1). Poultry oil containing the antioxidant Santaquin [7] was added at the rate of one pound per raw ton of fat to provide a residual of between 300 and 400 ppm. Hens were housed four birds per cage (length × width × height were 41 × 31 × 39 cm), and five adjacent cages were considered an experimental group. A total of 960 hens were divided into 48 experimental groups of 20 hens per group, and eight groups were randomly assigned to one of six dietary treatments for 16 wk. Hens were kept in an
JAPR: Research Report
358 environmentally controlled house under summer conditions where daily house temperatures were maintained at approximately 29°C (84°F) during the day and 20°C (68°F) during the night to get a daily average of 26°C (78°F). However, unusually high summer temperatures with high humidity during the study exceeded the average temperature for several days. Temperatures exceeded 32.2°C (90°F) for approximately four wk and went over 34.4°C (94°F) for 6 d. Beginning at 20 wk of age, light allocation to hens was increased from 12 h/d in increments of 15 min/wk to reach a constant 16h:8h light-to-dark cycle. To determine hen performance, EP and mortality were recorded daily; FC weekly, and BW was measured at termination of the study. The EW and egg specific gravity (ESG [8]) were measured biweekly and monthly, respectively, from a 2-d collection of all eggs laid during the week. Economics of supplementing fat and increasing protein in the diet was determined at the prevalent feed and egg prices [9]. Data were statistically analyzed [10] with the General Linear Models procedure of SAS [11] to determine the influence of dietary fat and protein levels on EP, EW, ESG, FC, and mortality. Significance was considered when P < 0.05.
RESULTS AND DISCUSSION Egg Weight Consistent with previous reports [1, 12] inclusion of dietary fat had a beneficial effect on EW of commercial Leghorns (Table 2). Fat increased average EW from 51.5 to 52.0 g. In spite of hens experiencing summer-time temperatures, increasing dietary protein from 17.4 to 19.8% had a linear effect on EW, which also increased from 51.5 to 52.0 g. Dietary fat increased EW 0.8, 0.5, and 0.3 g at the 17.4, 18.7, and 19.8% protein levels, respectively. Inclusion of fat to the low protein diet increased EW equal to that of hens fed the high protein diet without fat. Egg Production Hens EP peaked at approximately 25 wk of age between 93 and 95% on each dietary treatment and sustained peaks above 90% for 12 wk, even under heat stress (data not shown). Adding fat or increasing dietary protein had no
effect on average EP (Table 2). These results were in agreement with previous research [3, 12]. Egg Mass Dietary fat had no effect on egg mass (Table 2). However, towards the end of the experiment at wk 16, inclusion of fat increased egg mass (P < 0.01) from 50.5 to 52.4 g/hen per day, an increase of 1.9 g/hen per day (data not shown). Egg Specific Gravity Inclusion of fat had no effect on ESG (Table 2). However, a decreasing trend in ESG was observed when fat was added to the diet. This decrease in ESG was expected for two reasons: reduced feed intake causing reduced calcium intake, and increased egg size due to added fat. Body Weight Inclusion of fat in the diet increased average BW of hens from 1398 to 1476 g (Table 2), an increase of 78 g. This increase in BW was consistent with a previous report [1], where 4% dietary fat increased BW by 53 g. Increasing dietary protein from 17.4 to 19.8% increased BW by 50 g but was not significant. These results were consistent with a previous report [1], where increasing dietary protein from 17 to 21% had no significant effect on BW. However, the results were not in agreement with another report [12], in which hens fed 16% protein had lower BW than hens fed 20% protein. Feed Consumption On average, hens consumed approximately 83 g feed/hen per day (Table 3), approximately 8 g below the recommended average for HyLine W36 hens [13]. A significant interaction was observed between fat and dietary protein on FC. Inclusion of fat decreased FC by 3.7 and 4.6 g at the higher (19.8%) and moderate (18.7%) protein levels, respectively, but not at the lower level (17.4%). Hens fed diets with supplemental fat appear to have adjusted for energy intake at the higher and moderate protein levels but not at the lower protein level. This was perhaps due to the lower fat or energy level in the 17.4% protein diet. The hen’s ability to regulate energy intake was influenced by the
SOHAIL ET AL.: DIETARY FAT AND ECONOMIC GAIN
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TABLE 2. Effect of dietary fat and protein on performance of commercial Leghorns (average 21 to 36 wk of age)
Treatment Fat Without (0) With (+) Pooled SEM Protein (%) 17.4 18.7 19.8 Pooled SEM Protein (%) × fat 17.4 × 0 17.4 × + 18.7 × 0 18.7 × + 19.8 × 0 19.8 × + Pooled SEM P-values for main effects Fat Protein Protein × fat
BW (g)
Egg production (%)
Egg mass (g/hen per d)
Egg specific gravity (unit)
51.5 52.0 0.15
1398 1476 16
90.2 90.2 0.47
46.44 46.90 0.28
1.0846 1.0843 0.0002
51.5 51.8 52.0 0.18
1412 1435 1462 20
90.4 89.4 90.7 0.57
46.53 46.30 47.18 0.34
1.0844 1.0845 1.0845 0.0002
51.1 51.9 51.6 52.1 51.9 52.2 0.25
1357 1466 1407 1466 1435 1494 28
90.1 90.7 90.0 88.8 90.4 91.0 0.81
46.0 47.0 46.4 46.2 46.9 47.5 0.48
1.0846 1.0842 1.0846 1.0843 1.0848 1.0843 0.0003
** L*A NS
*** NS NS
NS NS NS
NS NS NS
NS NS NS
Egg weight (g)
A Linear. *Significantly different (P < 0.05). **Significantly different (P < 0.01). ***Significantly different (P < 0.001).
protein and/or energy level in the diet, which may be related to reduced heat increment in hens fed the lower protein diet [4]. Feed Efficiency As with FC, an interaction was also observed between fat and protein on feed efficiency of hens (Table 3). Inclusion of dietary fat reduced the amount of feed to produce a dozen eggs at the higher and moderate protein levels but not at the lower protein and lower energy level. This again may be related to reduced heat increment in hens fed the lower protein diet [4]. Economics The economics of adding fat and increasing dietary protein were determined [9] at two typical price spreads of 17 and 5 cents per dozen between medium and large eggs (Table 4). At the 17-cent spread, increasing dietary protein from 17.4 to 19.8% without increasing dietary fat increased return (income over feed cost) from
16.8 to 19.1 cents per dozen eggs, an increase in return of 2.3 cents per dozen. Supplementing diets with fat at each protein level increased returns for both price spreads when compared with diets not containing added fat. The response of adding fat at 17.4% protein was greatest, increasing returns by 3.1 cents per dozen eggs compared with 2.3 cents at 18.7% and 1.4 cents at 19.8% protein. Adding fat to the low-protein diet (17.4%) produced 0.8 cents greater return per dozen than the high-protein diet (19.8%) without fat. However, the overall maximum return was obtained from hens fed the high-protein diet (19.8%) with supplemental fat, which was 20.5 cents per dozen eggs. When the price spread was 5 cents, increasing dietary protein from 17.4 to 19.8% was not economical. Hens fed diets with fat averaged between 0.2 to 0.4 cents per dozen more than hens fed diets without fat at the three protein levels. With 5 cents spread between medium and large eggs, increasing dietary protein was not economical with the fat and feed prices used.
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TABLE 3. Effect of dietary fat and protein on feed consumption and feed efficiency in commercial Leghorns (average 21 to 36 wk of age)
Treatment Fat Without (0) With (+) Pooled SEM Protein (%) 17.4 18.7 19.8 Pooled SEM Protein (%) × fat 17.4 × 0 17.4 × + 18.7 × 0 18.7 × + 19.8 × 0 19.8 × + Pooled SEM P-values for main effects and interactions Fat/energy Protein Protein × fat
Feed consumption (g/hen per d)
Feed efficiency (lb/dozen eggs)
84.4 82.4 0.447
2.48 2.43 0.013
83.3 83.2 83.8 0.600
2.45 2.46 2.44 0.018
83.2 83.4 85.5 80.9 85.6 81.9 0.849
2.45 2.46 2.51 2.41 2.50 2.38 0.018
*** NS **
** NS *
*Significantly different (P < 0.05). **Significantly different (P < 0.01). ***Significantly different (P < 0.001).
With the lower spread between medium and large eggs, feeding the low protein diet with fat was more economical. All diets in this trial are currently used by several large producers during winter, summer and heat-stress conditions as needed. Producers using fat use diets 1, 3, and 5 (Table 1). Producers who do not use fat use diets with the same
nutrient specifications, except that the diets contain no fat (diets 2, 4, and 6) resulting in lower energy levels. Higher fat and energy levels are used in the two higher-protein diets formulated based on protein [6], in an attempt to maximize EW under summer or heat-stress conditions. Summer conditions are defined when average house temperature (24 h) is maintained at about
TABLE 4. Economics of supplementing fat and increasing dietary protein in commercial Leghorns Price spread (¢/dozen eggs)A
Protein (%) Fat
17.4
18.7
19.8
B
Returns (¢/dozen eggs) 17
5
A
Without With Increased returnsC Without With Increased returns
16.8 19.9 3.1 −6.1 −5.8 0.3
17.9 20.2 2.3 −6.6 −6.2 0.4
19.1 20.5 1.4 −6.6 −6.4 0.2
Difference in price per dozen between medium and large eggs. Returns (R) were calculated using the equation: R = UBEP − NR − PC − FdC, where UBEP = Urner Barry Egg Price, NR = nest run into package product delivered, PC = production cost, and FdC = feed cost, as described by Roland et al. [9]. C Increased return (IR) for using fat was calculated using the equation: IR = [with fat − without fat]. B
SOHAIL ET AL.: DIETARY FAT AND ECONOMIC GAIN 78°F. Panting birds indicate heat-stress conditions. Under winter conditions average house temperature (24 h) is maintained at approximately 68°F. Lower dietary energy levels are used in winter because much more energy is consumed due to higher feed intake. Because there were reports [4] that higher protein levels can increase heat increment and adversely affect hen performance under summer conditions, a concern of producers who cannot or elect not to
361
use fat is how much protein diets can contain prior to adversely affecting hen performance due to increased heat increment. These studies clearly indicate that under the conditions of this study, the highest protein diet with or without fat had no adverse affect and was the most profitable when a high spread exists between medium and large eggs. The results also allow producers to calculate the economics of adding fat handling equipment.
CONCLUSIONS AND APPLICATIONS 1. The inclusion of fat in commercial Leghorn diets during summer increased EW at all protein levels. 2. Increased protein level up to 19.8% with or without fat had no adverse effect on hen performance due to increased heat increment. 3. Fat increased profitability at all protein levels but impacted profit more at the lowest protein level. The highest profit was obtained from hens fed the high-protein diet with fat when price spread was high (17 cents/dozen) between medium and large eggs. 4. Producers who don’t use fat are losing approximately 1.4 to 3.1 cents per dozen eggs during summer depending upon the dietary protein level, price spread between medium and large eggs, and the price of feed (protein and energy) and eggs. Hopefully, these data will help producers when calculating the economics of adding fat-handling facilities for commercial layers.
REFERENCES AND NOTES 1. Keshavarz, K., and S. Nakajima. 1995. The effect of dietary manipulations of energy, protein, and fat during the growing and laying periods on early egg weight and egg components. Poult. Sci. 74:50–61. 2. Keshavarz, K. 1995. Further investigations on the effect of dietary manipulations of nutrients on early egg weight. Poult. Sci. 74:62–74. 3. Grobas, S., J. Mendez, C. De Blas, and G. G. Mateos. 1999. Laying hen productivity as affected by energy, supplemental fat, and linoleic acid concentration of the diet. Poult. Sci. 78:1542–1551. 4. Musharaf, N. A., and J. D. Latshaw. 1999. Heat increment as affected by protein and amino acid nutrition. Worlds Poult. Sci. J. 55:233–240. 5. Hy-Line International, West Des Moines, IA. 6. Roland, D. A., Sr., M. M. Bryant, and J. Self. 1995. Econometrics feeding: Performance and profits of commercial Leghorns (phase 1) fed diets formulated based on protein versus lysine. Poult. Sci. 74(Suppl. 1):66. (Abstr.) 7. Novus International, Inc., St. Charles, MO.
8. Strong, C. F., Jr. 1989. Relationship between several measures of shell quality and egg-breakage in a commercial processing plant. Poult. Sci. 68:1730–1733. 9. Roland, D. A., Sr., M. M. Bryant, J. X. Zhang, D. A. Roland, Jr., S. K. Rao, and J. Self. 1998. Econometric feeding and management. 1. Maximizing profits in Hyline W36 hens by optimizing total sulfur amino acid intake and environmental temperature. J. Appl. Poult. Res. 7:403–411. 10. Steel, R. G. D., and J. H. Torrie. 1980. Principles and Procedures of Statistics. McGraw-Hill Inc., New York, NY. Regression analysis was also conducted to determine relationship between the variables. 11. SAS Institute. 1989. SAS/STAT User’s Guide. SAS Inst. Inc., Cary, NC. 12. Parsons, C. M., K. W. Koelkebeck, Y. Zhang, X. Wang, and R. W. Leeper. 1993. Effect of dietary protein and added fat levels on performance of young laying hens. J. Appl. Poult. Res. 2:214–220. 13. Hy-Line International. 2000. Hy-Line W36 Commercial Management Guide 2000–2001 Hy-Line International, West Des Moines, IA.
Influence of Dietary Fat on Economic Returns of Commercial Leghorns S. S. Sohail, M. M. Bryant, and D. A. Roland, Sr.1 Department of Poultry Science and Alabama Agricultural Experiment Station, Auburn University, Alabama 36849
Primary Audience: Nutritionists, Feed Manufacturers, Egg Producers SUMMARY The beneficial effect of dietary fat and protein on improving egg weight (EW) is well-documented. However, many egg producers do not supplement fat in commercial hen diets because of inadequate storing and mixing facilities. To improve egg size without using fat, higher protein levels are fed. However, dietary protein has a greater heat increment than fat that could adversely affect hen performance during summer. The maximum dietary protein level that can be economically fed with no added fat without having an adverse effect on hen performance during summer or heat stress is not known. A study was conducted under summer conditions to determine the maximum dietary protein level that could be economically fed without using fat and if money is lost by not using dietary fat during summer. Supplementing fat increased EW and BW of hens in the study. Increasing dietary protein had a positive linear effect on EW. Neither fat nor protein had an effect on egg production, egg mass, or egg specific gravity. Fat increased FC and feed efficiency at the two higher protein levels (19.8 and 18.7%) but not at the lower level (17.4%). Economics of using fat indicated that egg producers feeding diets without fat are losing approximately 1.4 to 3.1 cents per dozen eggs depending upon fat cost and the spread in price between medium and large eggs. Key words: egg weight, fat, Leghorn, profit, protein 2003 J. Appl. Poult. Res. 12:356–361
DESCRIPTION OF PROBLEM The effect of fat and protein on increasing egg weight (EW) of commercial Leghorns has been well-documented [1, 2, 3]. Many egg producers, however, do not use supplemental fat because of inadequate storing and mixing facilities, and they rely instead on protein to maximize egg size. Dietary protein has a greater heat increment than fat, adversely affecting hen performance during periods of high environmental temperatures [4]. There is concern about how high dietary protein levels can be during the summer or periods of heat stress. A review of 1
the literature indicated that the optimal dietary protein level that can be economically fed with no added fat without having an adverse effect on hen performance is not known. There is also insufficient data to allow producers to calculate the cost of not using fat in commercial Leghorn diets at different fat and egg prices. This research was conducted to compare 1) the influence of varying protein levels with or without fat on EW, egg production (EP), and feed consumption (FC) during summer, and 2) to gather data required for egg producers to calculate if it is economical to invest in equipment necessary to add fat.
To whom correspondence should be addressed: [email protected].
SOHAIL ET AL.: DIETARY FAT AND ECONOMIC GAIN
357
TABLE 1. Ingredients and nutrient composition of experimental diets Experimental diets Ingredient
1
2
3
4
5
6
(%) A
Corn 8.6% Soybean meal 48%A LimestoneB Hard shellB Dicalcium phosphateC Poultry oilD NaCl Vitamin premixE Mineral premixF G DL-Methionine NatuphosH Cost ($/ton) Calculated analysis ME, kcal/kg per lb CP, % Calcium,I % Total P, I % NPP,I % Sodium, % Methionine, % Methionine + cystine, % Lysine, % Tryptophan, % Chloride, % Threonine, %
51.74 31.92 7.91 2.00 1.16 4.24 0.39 0.25 0.25 0.13 0.05 146.29
56.92 30.99 7.92 2.00 1.15 0.00 0.39 0.25 0.25 0.13 0.05 137.97
55.24 28.98 7.92 2.00 1.18 3.65 0.39 0.25 0.25 0.14 0.05 141.57
59.70 28.18 7.93 2.00 1.17 0.00 0.33 0.25 0.25 0.14 0.05 134.41
60.86 25.20 7.93 2.00 1.19 1.75 0.39 0.25 0.25 0.17 0.05 134.08
62.90 25.02 8.05 2.00 0.97 0.00 0.39 0.25 0.25 0.17 0.05 130.44
1,305 19.77 4.25 0.55 0.32 0.18 0.46 0.77 1.10 0.25 0.26 0.75
1,217 19.77 4.25 0.55 0.32 0.18 0.46 0.77 1.09 0.25 0.27 0.74
1,305 18.66 4.25 0.54 0.32 0.18 0.45 0.75 1.02 0.23 0.27 0.70
1,229 18.66 4.25 0.54 0.32 0.18 0.45 0.75 1.01 0.23 0.27 0.70
1,280 17.33 4.25 0.53 0.32 0.18 0.47 0.74 0.92 0.21 0.27 0.64
1,243 17.41 4.25 0.53 0.32 0.18 0.47 0.74 0.92 0.21 0.27 0.65
A
Amino acid content of corn and soybean meal was determined by ion exchange chromatography. Calcium carbonate was supplied as limestone (16 × 120 U.S. mesh, 1.9 to 0.125 mm) and hardshell (4 × 8 U.S. mesh, 4.75 to 2.36 mm). C Dynafos; IMC-Agrico Feed Ingredients, Bannockburn, IL 60015. D Price of poultry oil was $12.75 per 100 lb. E Provided per kilogram of diet: vitamin A (as retinyl acetate), 8,000 IU; cholecalciferol, 2,200 ICU; vitamin E (as dl-alpha tocopheryl acetate), 8 IU; vitamin B12, 0.02 mg; riboflavin, 5.5 mg; D-calcium pantothenic acid, 13 mg; niacin, 36 mg; choline, 500 mg; folic acid, 0.5 mg; vitamin B1 (thiamin mononitrate), 1 mg; pyridoxine, 2.2 mg; d-biotin, 0.05 mg; vitamin K (menadione sodium bisulfite complex), 2 mg. F Provided per kilogram of diet: manganous oxide, 65 mg; iodine (ethylene diamine dihydriodide), 1 mg; ferrous carbonate, 55 mg; copper oxide, 6 mg; zinc oxide, 55 mg; sodium selenite, 0.3 mg. G Degussa Corporation, Ridgefield Park, NJ. H Natuphos contained 600-phytase units/g, BASF Corp., Mt. Olive, NJ. I Dietary Ca, total P, and NPP (nonphytate P) values were determined by chemical analysis and values adjusted for feed formulation. B
MATERIALS AND METHODS This experiment was conducted as a randomized block design with two fat (without and with fat) and three protein levels (17.4, 18.7, and 19.8%) using 21-wk-old Hy-Line W36 hens [5; Table 1]. The diet containing 17.4% protein is a commercial layer diet used during the winter, which was formulated based on lysine [6]. Diets containing 18.7 and 19.8% protein were formulated based on protein [6] and are used during summer or periods of heat stress. Poultry oil was
used as the source of fat to increase dietary energy (Table 1). Poultry oil containing the antioxidant Santaquin [7] was added at the rate of one pound per raw ton of fat to provide a residual of between 300 and 400 ppm. Hens were housed four birds per cage (length × width × height were 41 × 31 × 39 cm), and five adjacent cages were considered an experimental group. A total of 960 hens were divided into 48 experimental groups of 20 hens per group, and eight groups were randomly assigned to one of six dietary treatments for 16 wk. Hens were kept in an
JAPR: Research Report
358 environmentally controlled house under summer conditions where daily house temperatures were maintained at approximately 29°C (84°F) during the day and 20°C (68°F) during the night to get a daily average of 26°C (78°F). However, unusually high summer temperatures with high humidity during the study exceeded the average temperature for several days. Temperatures exceeded 32.2°C (90°F) for approximately four wk and went over 34.4°C (94°F) for 6 d. Beginning at 20 wk of age, light allocation to hens was increased from 12 h/d in increments of 15 min/wk to reach a constant 16h:8h light-to-dark cycle. To determine hen performance, EP and mortality were recorded daily; FC weekly, and BW was measured at termination of the study. The EW and egg specific gravity (ESG [8]) were measured biweekly and monthly, respectively, from a 2-d collection of all eggs laid during the week. Economics of supplementing fat and increasing protein in the diet was determined at the prevalent feed and egg prices [9]. Data were statistically analyzed [10] with the General Linear Models procedure of SAS [11] to determine the influence of dietary fat and protein levels on EP, EW, ESG, FC, and mortality. Significance was considered when P < 0.05.
RESULTS AND DISCUSSION Egg Weight Consistent with previous reports [1, 12] inclusion of dietary fat had a beneficial effect on EW of commercial Leghorns (Table 2). Fat increased average EW from 51.5 to 52.0 g. In spite of hens experiencing summer-time temperatures, increasing dietary protein from 17.4 to 19.8% had a linear effect on EW, which also increased from 51.5 to 52.0 g. Dietary fat increased EW 0.8, 0.5, and 0.3 g at the 17.4, 18.7, and 19.8% protein levels, respectively. Inclusion of fat to the low protein diet increased EW equal to that of hens fed the high protein diet without fat. Egg Production Hens EP peaked at approximately 25 wk of age between 93 and 95% on each dietary treatment and sustained peaks above 90% for 12 wk, even under heat stress (data not shown). Adding fat or increasing dietary protein had no
effect on average EP (Table 2). These results were in agreement with previous research [3, 12]. Egg Mass Dietary fat had no effect on egg mass (Table 2). However, towards the end of the experiment at wk 16, inclusion of fat increased egg mass (P < 0.01) from 50.5 to 52.4 g/hen per day, an increase of 1.9 g/hen per day (data not shown). Egg Specific Gravity Inclusion of fat had no effect on ESG (Table 2). However, a decreasing trend in ESG was observed when fat was added to the diet. This decrease in ESG was expected for two reasons: reduced feed intake causing reduced calcium intake, and increased egg size due to added fat. Body Weight Inclusion of fat in the diet increased average BW of hens from 1398 to 1476 g (Table 2), an increase of 78 g. This increase in BW was consistent with a previous report [1], where 4% dietary fat increased BW by 53 g. Increasing dietary protein from 17.4 to 19.8% increased BW by 50 g but was not significant. These results were consistent with a previous report [1], where increasing dietary protein from 17 to 21% had no significant effect on BW. However, the results were not in agreement with another report [12], in which hens fed 16% protein had lower BW than hens fed 20% protein. Feed Consumption On average, hens consumed approximately 83 g feed/hen per day (Table 3), approximately 8 g below the recommended average for HyLine W36 hens [13]. A significant interaction was observed between fat and dietary protein on FC. Inclusion of fat decreased FC by 3.7 and 4.6 g at the higher (19.8%) and moderate (18.7%) protein levels, respectively, but not at the lower level (17.4%). Hens fed diets with supplemental fat appear to have adjusted for energy intake at the higher and moderate protein levels but not at the lower protein level. This was perhaps due to the lower fat or energy level in the 17.4% protein diet. The hen’s ability to regulate energy intake was influenced by the
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TABLE 2. Effect of dietary fat and protein on performance of commercial Leghorns (average 21 to 36 wk of age)
Treatment Fat Without (0) With (+) Pooled SEM Protein (%) 17.4 18.7 19.8 Pooled SEM Protein (%) × fat 17.4 × 0 17.4 × + 18.7 × 0 18.7 × + 19.8 × 0 19.8 × + Pooled SEM P-values for main effects Fat Protein Protein × fat
BW (g)
Egg production (%)
Egg mass (g/hen per d)
Egg specific gravity (unit)
51.5 52.0 0.15
1398 1476 16
90.2 90.2 0.47
46.44 46.90 0.28
1.0846 1.0843 0.0002
51.5 51.8 52.0 0.18
1412 1435 1462 20
90.4 89.4 90.7 0.57
46.53 46.30 47.18 0.34
1.0844 1.0845 1.0845 0.0002
51.1 51.9 51.6 52.1 51.9 52.2 0.25
1357 1466 1407 1466 1435 1494 28
90.1 90.7 90.0 88.8 90.4 91.0 0.81
46.0 47.0 46.4 46.2 46.9 47.5 0.48
1.0846 1.0842 1.0846 1.0843 1.0848 1.0843 0.0003
** L*A NS
*** NS NS
NS NS NS
NS NS NS
NS NS NS
Egg weight (g)
A Linear. *Significantly different (P < 0.05). **Significantly different (P < 0.01). ***Significantly different (P < 0.001).
protein and/or energy level in the diet, which may be related to reduced heat increment in hens fed the lower protein diet [4]. Feed Efficiency As with FC, an interaction was also observed between fat and protein on feed efficiency of hens (Table 3). Inclusion of dietary fat reduced the amount of feed to produce a dozen eggs at the higher and moderate protein levels but not at the lower protein and lower energy level. This again may be related to reduced heat increment in hens fed the lower protein diet [4]. Economics The economics of adding fat and increasing dietary protein were determined [9] at two typical price spreads of 17 and 5 cents per dozen between medium and large eggs (Table 4). At the 17-cent spread, increasing dietary protein from 17.4 to 19.8% without increasing dietary fat increased return (income over feed cost) from
16.8 to 19.1 cents per dozen eggs, an increase in return of 2.3 cents per dozen. Supplementing diets with fat at each protein level increased returns for both price spreads when compared with diets not containing added fat. The response of adding fat at 17.4% protein was greatest, increasing returns by 3.1 cents per dozen eggs compared with 2.3 cents at 18.7% and 1.4 cents at 19.8% protein. Adding fat to the low-protein diet (17.4%) produced 0.8 cents greater return per dozen than the high-protein diet (19.8%) without fat. However, the overall maximum return was obtained from hens fed the high-protein diet (19.8%) with supplemental fat, which was 20.5 cents per dozen eggs. When the price spread was 5 cents, increasing dietary protein from 17.4 to 19.8% was not economical. Hens fed diets with fat averaged between 0.2 to 0.4 cents per dozen more than hens fed diets without fat at the three protein levels. With 5 cents spread between medium and large eggs, increasing dietary protein was not economical with the fat and feed prices used.
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TABLE 3. Effect of dietary fat and protein on feed consumption and feed efficiency in commercial Leghorns (average 21 to 36 wk of age)
Treatment Fat Without (0) With (+) Pooled SEM Protein (%) 17.4 18.7 19.8 Pooled SEM Protein (%) × fat 17.4 × 0 17.4 × + 18.7 × 0 18.7 × + 19.8 × 0 19.8 × + Pooled SEM P-values for main effects and interactions Fat/energy Protein Protein × fat
Feed consumption (g/hen per d)
Feed efficiency (lb/dozen eggs)
84.4 82.4 0.447
2.48 2.43 0.013
83.3 83.2 83.8 0.600
2.45 2.46 2.44 0.018
83.2 83.4 85.5 80.9 85.6 81.9 0.849
2.45 2.46 2.51 2.41 2.50 2.38 0.018
*** NS **
** NS *
*Significantly different (P < 0.05). **Significantly different (P < 0.01). ***Significantly different (P < 0.001).
With the lower spread between medium and large eggs, feeding the low protein diet with fat was more economical. All diets in this trial are currently used by several large producers during winter, summer and heat-stress conditions as needed. Producers using fat use diets 1, 3, and 5 (Table 1). Producers who do not use fat use diets with the same
nutrient specifications, except that the diets contain no fat (diets 2, 4, and 6) resulting in lower energy levels. Higher fat and energy levels are used in the two higher-protein diets formulated based on protein [6], in an attempt to maximize EW under summer or heat-stress conditions. Summer conditions are defined when average house temperature (24 h) is maintained at about
TABLE 4. Economics of supplementing fat and increasing dietary protein in commercial Leghorns Price spread (¢/dozen eggs)A
Protein (%) Fat
17.4
18.7
19.8
B
Returns (¢/dozen eggs) 17
5
A
Without With Increased returnsC Without With Increased returns
16.8 19.9 3.1 −6.1 −5.8 0.3
17.9 20.2 2.3 −6.6 −6.2 0.4
19.1 20.5 1.4 −6.6 −6.4 0.2
Difference in price per dozen between medium and large eggs. Returns (R) were calculated using the equation: R = UBEP − NR − PC − FdC, where UBEP = Urner Barry Egg Price, NR = nest run into package product delivered, PC = production cost, and FdC = feed cost, as described by Roland et al. [9]. C Increased return (IR) for using fat was calculated using the equation: IR = [with fat − without fat]. B
SOHAIL ET AL.: DIETARY FAT AND ECONOMIC GAIN 78°F. Panting birds indicate heat-stress conditions. Under winter conditions average house temperature (24 h) is maintained at approximately 68°F. Lower dietary energy levels are used in winter because much more energy is consumed due to higher feed intake. Because there were reports [4] that higher protein levels can increase heat increment and adversely affect hen performance under summer conditions, a concern of producers who cannot or elect not to
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use fat is how much protein diets can contain prior to adversely affecting hen performance due to increased heat increment. These studies clearly indicate that under the conditions of this study, the highest protein diet with or without fat had no adverse affect and was the most profitable when a high spread exists between medium and large eggs. The results also allow producers to calculate the economics of adding fat handling equipment.
CONCLUSIONS AND APPLICATIONS 1. The inclusion of fat in commercial Leghorn diets during summer increased EW at all protein levels. 2. Increased protein level up to 19.8% with or without fat had no adverse effect on hen performance due to increased heat increment. 3. Fat increased profitability at all protein levels but impacted profit more at the lowest protein level. The highest profit was obtained from hens fed the high-protein diet with fat when price spread was high (17 cents/dozen) between medium and large eggs. 4. Producers who don’t use fat are losing approximately 1.4 to 3.1 cents per dozen eggs during summer depending upon the dietary protein level, price spread between medium and large eggs, and the price of feed (protein and energy) and eggs. Hopefully, these data will help producers when calculating the economics of adding fat-handling facilities for commercial layers.
REFERENCES AND NOTES 1. Keshavarz, K., and S. Nakajima. 1995. The effect of dietary manipulations of energy, protein, and fat during the growing and laying periods on early egg weight and egg components. Poult. Sci. 74:50–61. 2. Keshavarz, K. 1995. Further investigations on the effect of dietary manipulations of nutrients on early egg weight. Poult. Sci. 74:62–74. 3. Grobas, S., J. Mendez, C. De Blas, and G. G. Mateos. 1999. Laying hen productivity as affected by energy, supplemental fat, and linoleic acid concentration of the diet. Poult. Sci. 78:1542–1551. 4. Musharaf, N. A., and J. D. Latshaw. 1999. Heat increment as affected by protein and amino acid nutrition. Worlds Poult. Sci. J. 55:233–240. 5. Hy-Line International, West Des Moines, IA. 6. Roland, D. A., Sr., M. M. Bryant, and J. Self. 1995. Econometrics feeding: Performance and profits of commercial Leghorns (phase 1) fed diets formulated based on protein versus lysine. Poult. Sci. 74(Suppl. 1):66. (Abstr.) 7. Novus International, Inc., St. Charles, MO.
8. Strong, C. F., Jr. 1989. Relationship between several measures of shell quality and egg-breakage in a commercial processing plant. Poult. Sci. 68:1730–1733. 9. Roland, D. A., Sr., M. M. Bryant, J. X. Zhang, D. A. Roland, Jr., S. K. Rao, and J. Self. 1998. Econometric feeding and management. 1. Maximizing profits in Hyline W36 hens by optimizing total sulfur amino acid intake and environmental temperature. J. Appl. Poult. Res. 7:403–411. 10. Steel, R. G. D., and J. H. Torrie. 1980. Principles and Procedures of Statistics. McGraw-Hill Inc., New York, NY. Regression analysis was also conducted to determine relationship between the variables. 11. SAS Institute. 1989. SAS/STAT User’s Guide. SAS Inst. Inc., Cary, NC. 12. Parsons, C. M., K. W. Koelkebeck, Y. Zhang, X. Wang, and R. W. Leeper. 1993. Effect of dietary protein and added fat levels on performance of young laying hens. J. Appl. Poult. Res. 2:214–220. 13. Hy-Line International. 2000. Hy-Line W36 Commercial Management Guide 2000–2001 Hy-Line International, West Des Moines, IA.