The Metabolizable Energy Value of Some Feed Ingredients for Young Chicks

The Metabolizable Energy Value of Some Feed Ingredients for Young Chicks J. A .

OLUYEMI, B . L.

FETUGA AND H .

N.

L.

ENDELEY

Department of Animal Science, University of Ibadan, Nigeria (Received for publication June 13, 1975)

POULTRY SCIENCE 55: 611-618,

INTRODUCTION

P

O U L T R Y production is expanding rapidly in many areas of the tropics and considerable interest is being shown in the formulation of high efficiency diets for all classes of poultry based on the locally available feed ingredients. T h e lack of information on the composition and energy values of most of the available feedstuffs has however slowed down attempts by nutritionists to achieve greater productivity through improved nutrition. Reports exists from elsewhere o n the metabolizable energy values of the more c o m m o n feed ingredients for poultry (Carpenter and Clegg, 1956; Hill era/., 1960;Potter and Matterson, 1960; Sibbald and Slinger, 1962; and Janssen and T e r p e s t r a , 1972), while there is a complete lack of information on feeds whose production are restricted mainly to the tropics. F o r the more c o m m o n feed ingredients, variable metabolizable energy values may be obtained for different batches due to differences in composition related to 611

1976

differences in cultivars, soil and climatic factors and processing condition. This report deals with the determination of the metabolizable energy value of s o m e c o m m o n feedstuffs and some less c o m m o n ones with potentials as major constituents of poultry diets. MATERIALS AND METHODS F o u r grain legumes harvested from the University of Ibadan Teaching and R e s e a r c h F a r m , namely: Lima bean (Phaseolus lunatus, Lin), Acacia seed {Acacia Spp.), C o w p e a {Vigna unguiculata) and B a m b a r a nut {Voandzeia subterranea) were fed either in the raw form or autoclaved at 121° C. at 15 I b . / s q . in. pressure for 20 m i n u t e s . T h e palm-kernel and groundnut meals as well as the fish meals, blood meal and meat and b o n e meal were obtained as commercial s a m p l e s . T h e other oilseeds used are not pressed for oil in commercial quantities and were therefore prepared for this feeding trial by first

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ABSTRACT Metabolizable energy (M.E.) and metabolizable energy corrected to nitrogen equilibrium (M.E.J were determined for raw and autoclaved samples of four grain legumes, seven oilseed meals and five animal protein concentrates, using 9-day old White Leghorn cockerels. The M.E. and M.E.n for the autoclaved legumes were superior to the raw, the improvement with autoclaving being most marked for bambara nut. Acacia seed had the least M.E. and M.E.n values among the legumes probably related to its high crude fibre content. The oilseed meals had M.E. and M.E.„ values lower than for the autoclaved grain legumes, similar values being obtained for soybean, Sesame and palm kernel meals and slightly higher values for groundnut. Distinctly lower values were obtained for coconut and cotton seed meals. Raw and autoclaved rubber seed had M.E. and M.E.n values of 4.96 ± 0.29 and 4.83 ± 0.08 and 4.58 ± 0.16 and 4.63 ± 0.12 respectively, which were significantly higher than the corresponding values of 2.46 ± 0.37 and 2.38 ± 0.04 for the defatted rubber seed meal, due to its much lower oil content. Among the animal proteins concentrates, the M.E. and M.E.n for blood meal (3.49 ± 03 and 3.44 ± 0.03), were higher than for white fish meal (274 ± 0.13 and 2.63 ± 0.07), Menhaden fish meal (2.86 ± 0.05 and 2.74 ± 0.12) and an unspecified fish meal sample (2.47 ± 0.24 and 2.22 ± 0.17). Meat and bone meal, had the least M.E. and M.E.n values (2.14 ± 0.11 and 2.02 ± 0.08 respectively). The variable M.E. values for the fish meals did not appear to be related to variation in oil content but may be due to reduced availability of nutrients resulting from poor or long storage.

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J. A. OLUYEMI, B. L. FETUGA AND H. N. L. ENDELEY

In each experiment, the birds were fed and watered ad libitum for 14-day periods, seven of adjustment and seven of collection. The total collection method was employed. Droppings were collected daily and weighed and samples taken and frozen at -5° C. until the end of the collection period when the samples were dried in a forced air circulation oven at 50° C. for 48 hrs. The dried samples were ground, allowed to equilibrate with air mois-

TABLE 1.—Composition of basal diet (%) Ingredients Ground yellow maize (10.42% protein) 43.7 Groundnut cake (51.46% protein) 36.5 Fish meal (69.4% protein) 4.5 Blood meal (82.84% protein) 3.7 Brewer's grains 2.0 Brewer's dried yeast 1.0 Dicalcium phosphate 2.5 Oyster shell 0.5 Vit.-Min. Premix1 0.6 Palm-oil 5.0 'The Vit.-Min. Premix used was a Pfizer Livestock Feeds' Product supplying the following vitamins per kg. diet: Vitamin A, 11785.51 I.U.; Vitamin D3, 1964.3 I.U.; Vitamin E, 4.91 I.U.; Choline chloride 147.32 mg.; Riboflavin, 5.40 mg.; Panthothenic acid, 9.82 mg.; Nicotinic acid, 24.55 mg.; Folic acid, 0.98 mg.; Vitamin K, 2.20 mg.; Vitamin B12, 9.82 ji-g.; and the following minerals per kg. of diet: Cobalt, 1.23 mg., Iodine, 0.98 mg.; Copper, 9.82 mg., Manganese, 55.0 mg.; Zinc, 49.11 mg. and Iron, 19.64 mg.; 245.53 mg. methionine was also supplied by the premix per kg. of diet.

ture and then refrigerated for later analysis. Nitrogen content of feed, faeces and urine was determined by the Kjeldahl procedures (A.O.A.C, 1970). Gross energy of feed and faeces was determined with a Gallenkamp oxygen ballistic bomb calorimeter. The metabolizable energy of the test ingredients were calculated according to the equation: M.E. kcal. per gram test ingredient

M.E. kcal.per =

gram basal diet

M.E. kcal per gram test

M.E. kcal. per — gram basal

diet

diet.

_l

gram test ingredient per gram test diet. The metabolizable energy data were sub-

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coarse milling, followed by compression in a hand screw-press expeller (S. H. Johnson & Co. Ltd., London). The cotton seeds were degossypolised by moist heating prior to expelling of oil. The residual meals obtained from the expeller process were further defatted by adding finely ground meals in 1 kg. quantities to petroleum ether (B.P. 40-60° C.) in glass columns, 115 cm. high and 10 cm. in diameter. Residual ether was removed by spreading samples thinly over smooth clean platforms and sundrying. Soyabean meal and a sample of undefatted rubber seed meal were further treated by autoclaving at 121° C. at 15 Ib./sq. in. pressure for 20 minutes. Three consecutive experiments were conducted with 135, 150 and 90, 9-day old White Leghorn cockerels initially averaging 55.0, 58.5 and 56.8 g. respectively. These were obtained as day old chicks, caged in electrically heated battery brooders, where a 24% protein starter diet was provided ad libitum, until they were transferred to specialized metabolism cages (Armstrong Whitworth Model 2 / E type), where they were randomly assigned to the experimental treatments with five birds to each of three replication per treatment. The first, second and third experiments measured the metabolizable energy values of grain legumes, oilseed meals and some animal protein concentrates respectively. The unaltered basal diet (Table 1 was fed as a reference in each experiment. The test diets were formulated by adding 40% by weight of the test ingredient to 60% of the basal diet.

613

METABOLIZABLE ENERGY VALUES

jected to analysis of variance and difference between means tested using the Duncan's new multiple range comparison of treatment means (Steele and Torrie, 1960). RESULTS AND DISCUSSION

Table 3 summarizes the metabolizable energy (M.E.) and metabolizable energy values corrected for nitrogen retention (M.E. n ) for

TABLE 2.—Average proximate composition^ of test ingredients (g./lOO gm. dry sample)

Ash

Nitrogen free extract

Calcium

Phosphorus

0.75 0.74 1.24

4.66 4.59 5.38

64.73 66.57 62.58

0.57 0.56 0.64

0.50 0.50 0.26

10.34 2.46 2.53 4.47

1.16 2.54 2.61 6.11

5.42 5.68 5.72 4.80

62.06 63.70 63.78 61.79

0.59 0.14 0.16 0.39

0.31 0.46 0.47 0.49

22.74

4.38

5.94

4.76

62.18

0.39

0.46

51.46 18.70

4.21 12.96

5.28 6.48

6.04 4.80

33.01 57.06

0.48 0.18

0.65 0.74

22.54

3.80

49.49

3.47

20.70

0.93

0.65

23.14

3.79

47.58

3.86

21.63

0.86

0.71

36.40 50.82 46.42 48.22 26.82

4.40 5.16 11.87 6.38 17.48

8.54 7.74 4.98 11.39 8.45

5.33 6.36 6.40 10.45 6.87

45.33 29.92 30.33 23.56 40.36

1.14 0.27 0.15 0.36 0.15

0.82 0.82 0.89 1.04 0.34

Animal Protein Concentrates Fish meal (Unspecified) 68.94 Fish meal (white) 69.46 Fish meal (Menhaden) 66.62 Blood meal 82.54 Meat and bone meal 51.46

0.11 1.10 0.98 0.05 1.96

8.73 4.82 8.42 0.11 10.42

14.66 23.64 21.3 5.34 29.43

7.56 0.88 2.08 11.96 6.73

5.% 7.87 5.97 0.68 13.26

3.89 3.60 3.20 0.31 7.17

Ingredients Grain legumes Lima bean (raw) Lima bean (autoclaved) Acacia seed (raw) Acacia seed (autoclaved) Cowpea (raw) Cowpea (autoclaved) Bambara nut (raw) Bambara nut (autoclaved) Oilseed meals Groundnut meal Palm kernel meal Whole rubber seed meal (raw) Whole rubber seed meal (autoclaved) Defatted rubber seed meal Soyabean meal Cotton seed meal Sesame meal Coconut meal

Crude protein

Crude fibre

Ether extract

23.43 23.18 20.68

4.88 4.92 10.12

21.02 25.62 25.36 22.83

tMean of two determinations per sample.

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The proximate composition of the test ingredients is presented in Table 2. The grain legumes as a group showed crude protein content varying within very narrow limits (20.68-25.62), low ether extract and reasonably low crude fibre contents except in the case of both the raw and autoclaved Acacia seeds which had a distinctly higher fibre content. The composition of the oilseeds and animal protein concentrates are remarkably similar to earlier analysis (Oyenuga, 1968; Owusu-Domfeh et a/., 1970; and Oyenuga

and Fetuga, 1975). The reported crude protein contents for undefatted rubber seed meal is higher than the value of 18.3% reported by Orok and Bowland (1974) for some Nigerian rubber seed sample imported into Canada, but similar to a value of 22.1% reported by F.A.O. (1972) for some East Asian samples. The value for the defatted samples is also higher than the range of 29.35-31.59% reported by Buvanendran and Sinwardene (1970) for some Ceylonese samples. Their meals were however obtained by the expeller process and had a higher residual oil content than ours which were further solvent extracted.

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J. A. OLUYEMI, B. L. FETUGA AND H. N. L. ENDELEY

TABLE 3.—The metabolizable* energy value of some raw and autoclaved grain legumes for broiler chicks Energy value (kcal./g.)

%G.E

G.E.

M.E.

M.E. n

M.E.

Lima bean (raw) Lima bean (autoclaved) Acacia seed (raw) Acacia seed (autoclaved) Cowpea (raw) Cowpea (autoclaved) Bambara groundnut (raw) Bambara groundnut (autoclaved)

4.58 ± 0 . 1 8

3.50 ± 0.12

3.38 ± 0 . 1 2

76.42

"M.E.„ 73.80

4.49 ± 0.21

3.90 ± 0.04

3.67 ± 0.15

86.86

81.74

4.58 ± 0.14

2.98 ± 0.03

2.74 ± 0 . 1 9

65.07

59.83

4.58 ± 0.21 4.26 ± 0.08

3.04 ± 0.12 3.16 ± 0.08

3.00 ± 0.17 2.86 ± 0.14

66.38 74.17

65.50 67.14

4.27 ± 0.06

3.30 ± 0.11

3.11 ± 0 . 0 5

77.28

72.83

4.45 ± 0.015

1.95 ± 0 . 2 2

2.04 + 0.12

43.82

45.84

4.48 ± 0.04

3.96 ± 0.28

3.84 ± 0 . 1 8

88.39

85.71

*In this and subsequent tables M.E. and M.E.n values are means of triplicate groups fed the test diets. the raw and autoclaved forms of some grain legumes. Autoclaved bambara nut had distinctly higher M.E. values and superior efficiency of G.E. utilisation compared to autoclaved cowpea and Acacia seeds. In the group of legumes, Acacia showed the lowest M.E. values while the value for cowpea was intermediate. The lower M.E. values of the Acacia seed meal could be attributed to its higher fibre content, which would tend to lower its digestibility and therefore lower the metabolizable energy value. In almost all cases, autoclaving tended to improve the M.E. values of all the legumes tested and suggest the presence of protease inhibitor substances which were destroyed on heating. Maust et al. (1972), had obtained superior M.E. value for autoclaved cowpeas compared to the raw and germinated samples. Also the values of 3.16 ±0.08 and 2.86 ± 0.14 kcal./g. reported in this work for M.E. and M.E. n of raw cowpea are higher than the M.E. of 2.49 kcal./g. reported for raw cowpea by Maust et al. (1972), while our value of 3.30 kcal./g. for the autoclaved forms is very similar to the value of 3.29 kcal./g. reported for their autoclaved samples. The differences in the utilisation in the raw forms may be related

to differences in levels of anti-nutritional factors in the different samples assayed. Despite the similarity of M.E. values observed in this study and those reported by Maust et al. (1972) for autoclaved cowpea the lower gross energy value of our samples indicate slightly better efficiency of utilisation in our samples compared to theirs. The observed differences in the percent G.E. metabolised among the legumes may be related to differences in the component carbohydrates. The relative proportions of the simpler to the more complex carbohydrate constituents in each sample may affect the extent of its digestion and variations in the digestion of the nutrients in feeds accounts for most of the differences between feeds in their energy values. The M.E. and M.E. n values for some common and less common oilseed meals with potentials as dietary ingredients in poultry diets are presented in Table 4. Raw and autoclaved whole rubber seed show highly significantly higher values compared to the other meals for reasons of their high fat content, the value for the defatted rubber seed meals being lower than for most of the other meals except coconut and cotton seed

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Feedstuff

615

METABOLIZABLE ENERGY VALUES

TABLE 4.—The metabolizable energy value of some oilseed meals for broiler chicks Energy value (kcal./g.) Feedstuff

M.E.

M.E. n

M.E.

"M.E.„

4.48

2.46 ± 0.37

2.38 ± 0.04

54.91

53.13

6.99

4.58 ± 0.16

4.63 ± 0.12

65.52

66.24

7.11 4.46 4.69 4.83 4.88 4.42

4.96 2.74 2.98 2.69 2.67 2.48

2.83 2.69 2.89 2.56 2.61 2.39

± 0.08 ±0.12 ± 0.07 ±0.12 ± 0.06 ± 0.18

69.76 61.43 63.54 55.69 54.71 56.11

67.93 60.31 61.62 53.00 53.48 54.07

4.63

2.32 ± 0.36

2.26 ± 0.24

50.11

48.81

± 0.29 ± 0.05 ±0.18 ± 0.06 ± 0.04 ±0.11

meals. The authors are unaware of any published values for M.E. of rubber seeds for poultry. A report by Orok and Bowland (1974) gives the gross energy value of undefatted rubber seed meal as 6.50 kcal./g., while in the present study the corresponding G.E. for autoclaved and raw rubber samples were 6.99 and 7.11 kcal./g., respectively. The higher G.E. values reported by us are likely-to be related to a higher oil content in our samples (47.58 and 49.49% fat) compared to the ether extract value of 43.4% reported by Orok and Bowland (1974). The high M.E. value of whole rubber seed could be used to advantage in the formulation of high efficiency diets for poultry as this meal would also supply about 18-22% protein and fair amounts of the essential amino acids (Fetuga et al., 1975; and Orok and Bowland, 1974). The values reported for sesame oil meal, soybean meal, and palm kernel meal were fairly similar, while that for groundnut meal was slightly higher. Coconut meal and cotton seed meal had lower M.E. values. Compared to some earlier determination from elsewhere, the M.E. value of 2.98 ± 0.18 kcal./g. obtained for groundnut is distinctly higher than those of 2,530, 2,244, 2,240 kcal./kg. reported by Janssen and Terpestra (1972), Potter and Matterson (1960) and Fraps and Carlyle (1942), respectively, but comparable to value

of 2,926 kcal./kg. reported by Zablan et al. (1963) for groundnut cake. Similarly our values for 50% protein soybean meal was higher than those of 2,450 and 2,300 kcal./kg. reported by Janssen et al. (1972) and Squibb (1971), respectively. It was however fairly similar to the value of 2,728 kcal./kg. reported by Sibbald and Slinger (1962). The lower values observed for coconut meal and cotton seed meal may be related to an impairment of their digestibility by a high crude fibre content. Palm kernel meal with a similarly high crude fibre content, showed a much higher M.E. and M.E. n values compared to this meal. Earlier studies with rats (Fetuga et al., 1973a) and pigs (Fetuga et al., 1973b) clearly showed the digestibility of nutrients in palm kernel meal to be impaired by its high fibre content. The fairly high M.E. and M.E. n values obtained for this feedstuff with chicks is therefore surprising. McDonald et al. (1973) reported a much lower value of 1,610 kcal./kg. M.E. for this feedstuff. A previous study with pigs (Oyenuga and Fetuga, 1975), had also obtained D.E. and M.E. values for several of the commercially available oilseed cakes, higher than most reports from Europe and North America. These observed higher values are likely related to variations in composition of these residual cakes and meals. With oilseed meals

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Defatted rubber seed meal Whole rubber seed (autoclaved) Whole rubber seed (raw) Palm kernel meal Groundnut meal Soybean meal Sesame oil meal Coconut meal Cotton seed meal

<%G.E

G.E.

616

J. A. OLUYEMI, B. L. FETUGA AND H. N. L. ENDELEY

The M.E. and M.E. n values for three fish meal samples, all of which were imported into Nigeria, locally produced meat and bone meal and blood meal appear in Table 5. Blood meal gave significantly (P < 0.05) the highest value, followed by the white and Menhaden fish meal which gave fairly similar values. The value for the unspecified fish meal sample was lower in comparison, while that for meat and bone meal was least. The M.E. and M.E. n values obtained for bone and meat meal in the present study is higher than that

of 1716 kcal./kg. reported for a 44% protein meat and bone meal sample by Potter and Matterson (1960). These authors also report a value of 3.21 kcal./g. for blood meal while our value was 3.49 kcal./g. Meat and bone meal and blood meal are highly variable products. The composition of meat and bone meal would vary considerably depending on such factors as the amounts of connective tissue and bone included in the product during processing, which would in turn influence the relative content of calcium and phosphorus resulting in variable availability of metabolizable nutrients in different batches of the same ingredient. Blood meal samples can also vary in composition and utilization of nutrients depending on the extent of contamination with gut contents and feathers as well as with processing method. Studies by Fetuga et al. (1973a, b) with rats and pigs on blood meal from the same source and of similar composition as that used in the present study obtained dry matter and protein digestibility above 90%. This high digestibility may account for the fairly efficient utilisation of its gross energy. The M.E. value of 2.74 kcal./g. obtained for white fish meal is similar to the value of 2794 kcal./kg. obtained by Sibbald and Slinger (1962), but it is distinctly higher than that of 2002 kcal./kg. obtained by Hill et al. (1956). Potter and Matterson (1960) reported a value of 2728 kcal./kg. for the same type of fish meal. Differences between the unspecified fish meal sample and white and

TABLE 5.—The metabolizable energy value of some animal protein concentrates for chicks Energy value (kcal./g.) Feedstuff Fish meal (Unspecified) Fish meal (White) Fish meal (Menhaden) Meat and bone meal Blood meal

%G.E

G.E.

M.E.

M.E.„

M.E.

M.E. n

4.67 ± 0.24

2.47 ± 0.24

2.22 ± 0 . 1 7

52.89

47.54

4.79 ± 0.14

2.74 ± 0.13

2.63 ± 0.07

57.20

54.91

4.88 ± 0.09

2.86 ± 0.05

2.74 ± 0.12

58.61

56.15

4.24 ± 0.04 4.38 + 0.12

2.14 ± 0.11 3.49 + 0.03

2.02 ± 0.08 3.44 + 0.03

50.47 79.68

47.64 78.54

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in particular, the G.E.,D.E. andM.E. values may vary widely for different batches of the same feedstuff, particularly because of the variable levels of residual oil in these meals. In Nigeria, most of the commercial oil mills employ the expeller process, while in some other countries, a combination of expeller and solvent extraction processes are used to obtain greater efficiency of oil removal from oilseeds leaving residues of very low oil content. Analysis of several batches of commercially available groundnut and palm kernel meals used in Nigeria over a four year period (Fetuga, 1972), showed variation in ether extract and gross energy of groundnut to be in the range 4.4 to 8.9% and 4.47 to 5.14 kcal./g. and in palm kernel meal in the range 5.7 to 8.7% and 4.20 to 4.79 kcal./g. Such variations in the residual oil content, related to the fairly inefficient oil removal by the expeller process in common use may account for the higher G.E. and therefore also the higher M.E. values observed.

617

METABOLIZABLE ENERGY VALUES

In general higher values were obtained for t h e autoclaved grain legumes relative to the oilseeds and animal protein c o n c e n t r a t e s . T h e lower protein and higher c a r b o h y d r a t e of legumes relative to oilseeds and the animal protein concentrates could have resulted in higher M . E . because c a r b o h y d r a t e has a lower specific dynamic action than protein a n d may be better absorbed than this nutrient. Based on a comparison of our d a t a with some published work on the more c o m m o n ingredients the agreements and disimilarity in values reported indicate that published M . E . values cannot be expected apply to all situations. At best selected values from several determinations of M . E . for different batches of the same ingredient would have to be used in diet formulation and selection must take cognisance particularly in the case of oilseed meals of the level of residual oil and in other cases similarity in composition and processing techniques to the samples for which published M . E . values are available.

ACKNOWLEDGEMENT T h e authors wish to a c k n o w l e d g e the financial support of the R e s e a r c h grant committee of the Senate of the University of

Ibadan w h o provided the funds from which this work was carried out. W e are particularly indebted to Messrs Adiatu Buari and A n t h o n y Akwobi for the assistance rendered in care and feeding of experimental birds and finally our thanks also go to Miss Olabisi Olufuwa for technical assistance in Chemical Analysis and energy determinations.

REFERENCES Association of Official Analytical Chemists, 1970. Official Methods of Analysis. Association of Official Analytical Chemist Washington D.C. Buvanedran, V., and J. A. de S. Siriwandene, 1970. Rubber seed meal in poultry diets. Ceylon Vet. J. XVIII (2): 33-38. Carpenter, K. J., and K. M. Clegg, 1956. The metabolisable energy of poultry feedingstuffs in relation to their chemical composition. J. Sci. Food Agric. 7:45-51. Food and Agriculture Organisation of the United Nations, 1972. Food Composition Table for Use in East Asia. Food Policy and Nutrition Division, FAO of UN, 00100—Rome, Italy. Fetuga, B. L., 1972. Assessment of the protein quality of some Nigerian foods and feedingstuffs in the nutrition of the pig and rat. Ph.D. Thesis. University of Ibadan. Fetuga, B. L., G. M. Babatunde and V. A. Oyenuga, 1973a. Protein quality of some Nigerian feedstuffs. II. Biological evaluation of protein quality. J. Sci. Food Agric. 24: 1515-1523. Fetuga, B. L., G. M. Babatunde and V. A. Oyenuga, 1973b. Evaluation of the protein quality of some Nigerian protein concentrates with young pig. Niger. Agric. J. 10(2): 208-218. Fetuga, B. L., G. M. Babatunde and V. A. Oyenuga, 1975. The potentials of para-rubber seed meal in human and livestock feeding. Proc. 1st African Nutrition Congress, 17-22nd March 1975, University of Ibadan, Nigeria (In Press). Fraps, G. S., and E. C. Carlyle, 1942. Productive energy of some feeds and foods as measured by gains of energy by growing chicks. Texas Agric. Exp. Sta. Publ. No. 625. Hill, F. M., D. L. Anderson, R. Renner and I. B. Carew, Jr., 1960. Studies of metabolisable energy of grain and products for chickens. Poultry Sci. 39: 573-579. Hill, F. M., L. B. Carew and R. Renner, 1956. Studies of efficiency of energy utilization by growing chicks. Proc. Cornell Nutrition Conference for Feed Manu-

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M e n h a d e n fish meals reflect different degrees of deterioration in storage and transportation a n d not differences in fat c o n t e n t since t h e unspecified fish meal sample had a fat content comparable to the M e n h a d e n fish meal but higher than that of white fish meal (Table 2). Deterioration would result in reduced biological availability of nutrients particularly the amino acids. May and Nelson (1973), had evaluated the D . E . and M . E . values of some varieties of milo with rats and found that these values tended to increase as the biological availability of the amino acids to chicks increased. It would appear that factors that affect the overall availability of nutrients would influence the M . E . values of ingredients for all species.

618

J. A. OLUYEMI, B. L. FETUGA AND H. N. L. ENDELEY digestibility of nutrients and energy value to pigs of some oilseed meals and three commonly used cereals fed to pigs. East Afric. J. Agric. Forestry, 40 (In Press). Owusuh-Domfeh, K., D. A. Christensen and B. D. Owen, 1970. Nutritive value of some Ghanaian feedstuffs. Can. J. Anim. Sci. 50: 1-14. Potter, L. M., and L. D. Matterson, 1960. Metabolizable energy of feed ingredients for the growing chick. Poultry Sci. 39: 781-782. Sibbald, I. R., and S. J. Slinger, 1962. The metabolizable energy of materials fed to growing chicks. Poultry Sci. 41: 1612-1613. Squibb, R. L., 1971. Estimating the metabolizable energy of foodstuffs with an avian model. J. Nutr. 1011: 1211-1215. Steele, R. G. D., and J. H. Torrie, 1960. Principles and Procedures in Statistics. McGraw Hill Book Co., Inc., London. Zablan, T. A., M. Griffith, M. C. Neishen, R. J. Young and M. L. Scott, 1963. Metabolizable energy of some oilseed meals and some unusual feedstuffs. Poultry Sci. 42: 619-625.

Influence of Grinding, Cooking and Refrigerated Storage on Lipid Stability in Turkeyl L.

E. DAWSON AND K.

SCHIERHOLZ

Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824 (Received for publication June 19, 1975)

ABSTRACT Frozen whole torn turkeys were thawed at 3° C. and samples were either roasted whole or boned, ground and broiled as patties. TBA values were determined to estimate development of lipid oxidation in breast, thigh, skin and natural proportion combinations. TBA values were highest from ground, cooked patties held 7 days at 3° C , followed, respectively, by ground patties held 7 days, roasted meat held 7 days, freshly broiled patties, freshly roasted meat and freshly ground patties. Stability of turkey meat was therefore influenced by cooking, grinding and storage, and the combination resulted in maximum lipid oxidation. Variations in lipid stability among meat source (breast, thigh, skin) were less than among processing treatments. POULTRY SCIENCE 55: 618-622,

INTRODUCTION

T

H E instability of turkey lipids a s s u m e s economic importance since t u r k e y s are produced s o m e w h a t seasonally and are consumed throughout the year. Efforts should

1. Michigan Agricultural Experiment Station Journal Article No. 7305.

1976

be encouraged to better understand lipid oxidation and those factors affecting its rate in both frozen-raw and frozen-cooked products. There has been a rapid increase in development and consumption of new turkey p r o d u c t s , some of which h a v e a limited shelflife d u e t o "off" flavors developed during frozen storage. T h e increasing use of mechanically boned meat also affects stability

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