Utilisation of chick hatchery waste: The nutritional characteristics of day-old chicks and egg shells

Agri¢ultur~iIWaster4 (1982) 335 343

UTILISATION OF CHICK HATCHERY WASTE: THE NUTRITIONAL CHARACTERISTICS OF DAY-OLD CHICKS AND EGG SHELLS

A. G, J. TACON

Institute of Aquaculture, Uni~,ersity oj Stirling, Stirling FK9 4LA, Great Britain

ABSTRACT

The nutriti~,e t'alue o f male day-old chicks and egg shells was tiewed in terms (~/ their proximate, amino acid,./atty acid, mineral, vitamin and possible microbial content. Processed chick meal was described as an animal protein concentrate equivalent to meat meal. Chick shell meal was described as a mineral based product equivalent to a trace element enriched limestone or a phosphorus deficient steamed bone meal. The potential hazards' which may be associated with the use g f these products as animal ./~,edstu/fs are described.

INTRODUCTION

Recent increases in basic raw material and energy costs have placed renewed pressures upon the intensive animal-production systems to find profitable outlets for their by-products and wastes. In particular, a great deal of attention has been focused on the recycling of these animal by-products as feedstuffs for use in animal production (Ichhponani & Lodhi, 1976). Within the chick-hatchery industry, there is a considerable amount of animal waste produced, including unhatched eggs, dead embryos, culled chicks and egg shells. Of particular nutritional interest are the male chicks of laying strains, which at present have little or no commercial value. It is estimated that approximately 38 million chicks of this category are produced each year within the UK. Apart from the limited use of these culled chicks as a low-priced animal foodstuff, present day disposal practices include spreading on agricultural land and tipping as landfill (Humenik et al., 1978). 335 Agricultural Wastes 0141-4607/82/0004-0335/$02.75 Printed in Great Britain

~ Applied Science Publishers Ltd, England, 1982

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Despite the widely publicised high nutritive value of chick and egg hatchery waste by-products in general, little published information is available concerning the nutritional composition and merits of day-old chicks and egg shells. The aim of this investigation was, therefore, to carry out a detailed proximate and biochemical analysis of these products, and so provide the information required by feed formulators to realise their full nutritional potential as animal foodstuffs.

METHODS

Sample preparation Deep frozen, male, day-old chicks and egg shells were supplied by H. Reed, Joice and Hill (Hisex) Ltd, South Raynham, Norfolk. Within the laboratory, replicate samples were homogenised (in the case of thawed day-old chicks by passing through a Hobart A200 mincer), air-dried at 60 °C, finely ground using a rotary mill (1-mm sieve), and the resultant day-old-chick concentrates (chick meal, CM) and egg shells (chick shell meal, CSM) then stored in airtight containers at 4°C for subsequent chemical analysis. Chemical methods Replicate samples of CM and CSM were used for the determination of water, crude protein, lipid, crude fibre, ash, acid-insoluble ash, saponification value, available carbohydrate as glucose and mineral composition following the methods described previously (Tacon & Ferns, 1978/1979). Iodine value of the crude lipid extract and vitamin analyses were determined using the methods described by the Association of Official Analytical Chemists (1970). Amino acids were assayed by ion exchange chromatography using a Locarte amino acid analyser, following hydrolysis with 6 Y HC1 (Roach et al., 1967). Fatty acids were methylated by refluxing for 1 h with dry methanol containing 5 ~/oHC1, and the methyl esters analysed by gas liquid chromatography using a Pye Unicam Series 104 gas chromatograph. Other protein meals were analysed for amino acids using the method described for CM and CSM.

RESULTS AND DISCUSSION

On the basis of the results of the chemical analyses, the nutritive value of CM and CSM can be viewed in terms of the following components. Protein and amino acid composition The crude protein content and amino acid composition of CM and CSM are shown in Tables 1 and 2. Compared with conventional animal foodstuffs, CM is a

337

COMPOSITION OF CHICK AND EGG SHELL MEALS

TABLE 1 RANGES AND MEAN VALUES FOR THE GROSS CHEMICAL COMPONENTS OF CHICK MEAL (CM) AND CHICK SHELL MEAL (CSM), MEAN VALUES ARE EXPRESSED AS ~o BY WEIGHT

Component ~ Range Moisture Total N Crude protein (N × 6-25) Lipid Crude fibre Ash Iodine value c Saponification value d Calculated gross energy ~

Chick meal Mean

Chick shell meal Range Mean ++SE b

+ SE b

4.4 5.2 4.89 0-18 8.6-9.0 8.86 0.04 54-56 55-39 0.29 31 33 31.98 0.25 0.2 0.3 0.28 <0.01 7.5 7-8 7.61 0.08 75-104 89 6-0 147-178 166 7.0 6190 kcal kg - ~

1.4 1-5 2.2-2.3 13.7-14.2 0.09-0-13 3.9 5.8 86 87

1.46 0.03 2-24 0.02 14-03 0.12 0-10 <0-01 4.92 0-40 86.83 0.18 . . . . 810 kcal kg

° Other components determined : available carbohydrate as glucose < 0.1 },~: acid-insoluble ash < 0.1 'I,,. b Standard error, n = 5. c Defined as the number of grams of iodine absorbed by 100g of lipid. d Defined as the number of milligrams of alkali (KOH) required to neutralise the fatty acids present in 1 g of lipid. Assumes a calorific value of 5.7 kcal g a protein, 9.5 kcal g - ~ lipid, 4.1 kcal g - l carbohydrate.

TABLE 2 APPROXIMATE AMINO ACID COMPOSITION OF CHICK MEAL (CM) AND CHICK SHELL MEAL (CSM). VALUES ARE EXPRESSED AS g AMINO ACID 100g-1 MEAL, AND g AMINO

ACID 16 g 1 N

Amino acid

Chick meal % CM g l 6 g -1 N

Chick shell meal % CSM gl6g i N

Aspartic acid Serine Glutamic acid Proline Glycine Alanine Lysine Methionine Cystine Threonine Isoleucine Leucine Valine Phenylalanine Tyrosine Histidine Arginine Tryptophan °

3.9 2.7 6-5 3.9 3.7 3.3 4.0 1.2 2.3 2.1 2.3 3.3 2.8 2-5 1.9 1.1 3.3

7. l 4.8 11.7 7.0 6.8 5.9 7.3 2.1 4.2 3.7 4-1 6.0 5.1 4.5 3.4 2.1 6.0

0-69 0.40 1.04 0.76 0.86 0.36 0.32 0.23 0.89 0.44 0.33 0.45 0.51 0.20 0.22 0.28 0.67

4-9 2.9 7'4 5.4 6.1 2.6 2-3 1"6 6"4 3. l 2.4 3.2 3.6 1-4 1.6 2-0 4-8

Total EAA ~ Total AA c

26.8 50.8

48.5 91.8

4-54 8"65

32.4 61.7

a Destroyed during acid hydrolysis. Total summation of essential amino acids measured. Total summation of all essential and non-essential amino acids measured.

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g o o d source o f protein, the crude protein level ranging between 54 and 56 ~o by weight. This protein level is equivalent to that normally present in meat meal and poultry by-product meal. The crude protein content o f C S M , on the other hand, was low (14 ~o by weight), originating primarily from the organic shell m e m b r a n e on the inner surface of the shell matrix. The amino acid composition of C M and C S M is c o m p a r e d with several conventional protein foodstuffs in Table 3. As expected, the amino acid profile of

TABLE 3 ESSENTIAL AMINO ACID COMPOSITION OF SOME CONVENTIONAL AND UNCONVENTIONAL PROTEIN FOODSTUFFS. VALUES ARE EXPRESSED AS g AMINO ACID 1 6 g - l N

Amino acid

CM

CSM

Meat meal

Total N (~,) Lysine Methionine Cystine Threonine Isoleucine Leucine Valine Phenylalanine Tyrosine Histidine Arginine Tryptophan

8-9 7.3 2.1 4.2 3.7 4.1 6.0 5.1 4.5 3-4 2.1 6"0

2.2 2.3 1.6 6.4 3.1 2-4 3.2 3.6 1.4 1.6 2.0 4.8 --

8.8 5.5 1.4 1.2 3.3 3.5 6-4 4.7 3-5 1.6 2.0 6.7 0.6

Poultry' Hydrolysed Soyabean Herring by-product feather meal meal meal meal

9.3 4.4 1.8 1.7 3.5 4.0 7-6 4.6 3.1 1.5 2.8 6-6 09

13-6 1.2 0.6 3.5 3.3 3.2 9.2 5.4 3.2 2.7 0-3 4.6 0.5

7.0 6.6 1.5 1.5 3.9 5.7 7-7 5.4 5.0 2.9 2.5 7.7 1.6

11.5 7.9 3-1 1-0 4.0 4.2 7.1 7.9 3.6 3.4 2.6 7.8 1.1

FAO reJla protein

-4.2 2-2 2-0 2.8 4.2 4.8 4.2 2.8 2.8 1.4

° Data from FAO (1957).

C M compares very favourably with that of herring meal. C M is a g o o d source of methionine and lysine, and is a particularly rich source of cystine. A l t h o u g h cystine has a sparing effect on the requirement for methionine, there may be some cause for concern for the very high levels found in C M and CSM, since it is believed that the high cystine content of feather protein (keratin) may be a limiting factor in the utilisation of this protein in animals (Ichhponani & Lodhi, 1976). Despite the low crude-protein content of C S M , summation of essential and nonessential amino acids measured indicated that a high proportion o f the total N within C S M was in the form o f n o n - a m i n o acid N-containing c o m p o u n d s (N PN ; as indicated by the summation o f amino acids (g 16 g - i N), Table 2). Significant levels o f N P N , mainly in the f o r m o f hexosamines, have been previously reported in the shell gland fluid and organic constituents o f the hen's egg shell (Salevsky & Leach, 1980). The presence of significant a m o u n t s o f N P N within CSM, in the form of polymeric (N-acetyl) hexosamines, m a y also in part explain the high crude-fibre content of this product (Table 1).

C O M P O S I T I O N OF C H I C K A N D E G G S H E L L MEALS

339

Lipid and f a t t y acid composition The lipid content and fatty acid composition of CM and CSM are shown in Tables 1 and 4. Compared with conventional protein foodstuffs, CM has an extremely high lipid content, ranging between 31 and 33 ~o by weight. A similar lipid content has been reported for broiler and egg-type poultry-by-product meal (Vandepopuliere et al., 1977). The high lipid content of CM will almost certainly be a limiting factor in the utilisation of this product as an animal foodstuff at high

TABLE 4 PROPORTIONS OF FATTY ACIDS (AS WEIGHT ~0 TOTAL FATTY ACIDS) IN CHICK MEAL (CM) Fatty acid

14:0 Myristic acid 16:0 Palmitic acid 16:1 Palmitoleicacid 18:0 Stearic acid 18:10leic acid 18:2 Linoleicacid 20: Unsaturates % saturated % monounsaturated % polyunsaturated

Chick meal

0.5 28.4 2.6 9.0 44.0 14.8 0-7 37.9 46.6 15.5

dietary levels of inclusion. The lipids contained within CM were composed almost entirely of saturated and monounsaturated fatty acids (predominantly oleic and palmitic acids), with only a relatively small proportion being present in the form of the diunsaturated essential fatty acid, linoleic acid (Table 4). Although no carotenoid analyses were performed on these samples, it is highly likely that the lipid fraction of CM will contain a certain amount of carotenoid pigment originating from the remains of the yolk sac within the day-old chicks. These pigments, if present in significant concentrations, may confer unwanted pigmentation on the flesh of the animal consuming the product. Mineral content The ash content and mineral composition of CM and CSM are shown in Tables 1 and 5. Compared with conventional protein sources, CM is a good dietary source of the major elements Ca, P, Na, K and NaCI, and to a lesser extent Mg and Fe. Similarly, on the basis of the trace elements analysed, CM is a good source ofCu, Ni and Cr, but is a poor source of Mn. From a toxicological viewpoint, however, CM does contain an extremely high level of Zn (1676ppm by weight), and to a lesser extent Pb (14ppm by weight), compared with conventional protein sources. A serious problem that may arise from the use of CM as a feed additive, therefore, is the possibility of these elements causing injury to health, either through mineral

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TABLE 5 RANGESAND MEANVALUESFOR 16 MINERALSWITHINCHICKMEAL(CM) AND CHICKSHELLMEAL(CSM). MEAN VALUES ARE EXPRESSED AS ~ooOR P.P.M. BY WEIGHT Mineral Range. Ca (%) P (%) NaC1 (~o) Na (%) K(~) Mg (%)

1.33 1.39 1.22 1.27 0.96-1.00 0.58-0.61 0-52 0.56 0.06-0-07

Zn (p.p.m.) Fe (p.p.m.) A1 (p.p.m.) Cu (p.p.m.) Mn (p.p.m.) Pb (p.p.m.) Ni (p.p.m.) Cr (p.p.m.) Cd (p.p.m.) As (p.p.m.)

1590 1 7 3 8 104-149 21.8-29-7 8.68 10.45 0.46-1-36 12.3 17.4 6.12 11.19 1.53 2-17 0.70 0.92 < 1

Chick meal Mean

Chick shell meal Mean

+_SE

Range

+ SE a

1.36 1.24 0.98 0.60 0.55 0-07

0-01 0.01 0.01 <0.01 0-01 <0.01

30-33 0.06 0.08 0-11 0.12 0.26 0-27 0.12 0.13 0-36 0.37

31.25 0.07 0.11 0.26 0.12 0.37

0.71 <0.01 <0.01 <0.01 <0.01 <0.01

1676 127 25-07 9.46 1.00 14.23 8.82 1-78 0.79 < 1

36.2 9.2 1.6 0.39 0.05 1.21 1-05 0.15 0.06

6.50-13.0 115 120 31.0-38-6 8.9 9.1 1.62-9.28 67-70 22-25 14-16 3-60 3-78 < 1

10-2 118 34-0 9-0 5.82 68.3 23-3 15.0 3.75 < 1

1.6 1.5 1.2 <0.01 0.21 0-7 0.7 0.1 <0.01

" Standard error, n = 5.

imbalance or through progressive accumulation in the body. The high Zn content of CM is almost certainly derived from the high concentrations of this element normally found within the skin and feathers of day-old chicks. Although Zn toxicity has been reported in some farm animals fed Zn-contaminated feeds, the majority of animals have a high tolerance for this element. However, excessive Zn intakes are known to depress food consumption and may induce Cu deficiency in animals (McDonald et al., 1976). As expected, CSM was found to have a very high ash content, ranging between 86 and 87% by weight (Table 1). The ash fraction of CSM was composed almost entirely of CaCO 3, the Ca content of CSM being equivalent to that of limestone. Similarly, CSM is a good source of Mg, Fe, Cu, Ni and Cr, but is a very poor source of P, and to a lesser extent Zn. The high Cr content of CSM may be of particular nutritional importance, since it has been shown to be an essential trace element in animal nutrition (Underwood, 1971). Trivalent Cr acts as a cofactor with insulin, and therefore is necessary for normal glucose metabolism (Mertz, 1969). In this respect, Cr deficiency mimics diabetes mellitus and produces aortic plaques in rats (Hambridge, 1974). Similarly, the involvement of trivalent Cr in fatty acid metabolism is such that it has been suggested that Cr deficiency may be a basic factor in atherosclerosis, since deficiences are known to raise plasma cholesterol concentrations (Mertz, 1969). From a toxicological viewpoint, however, CSM is highly contaminated with Pb (68ppm by weight), and to a lesser extent Cd (3.75ppm by weight). It may be that these elements are deposited into the shell matrix of the hens egg as a means of eliminating them from the parent body burden.

COMPOSITION OF CHICK AND EGG SHELL MEALS

341

Vitamin content

The content of a few selected vitamins within CM is shown in Table 6. The absence of the fat-soluble vitamins, A and D, within CM is perhaps surprising since these vitamins should have been present within the macerated liver and kidney tissues of day-old chicks. However, it is likely that these vitamins were destroyed during the dehydration phase of the preparation of CM. Of the remaining vitamins analysed, CM was found to be a good dietary source of niacin (nicotinic acid) and TABLE 6 THE C O N T E N T OF A F E W SELECTED VITAMINS W I T H I N C H I C K MEAL ( C M) . V A L U E S ARE EXPRESSED AS P . P . M . BY W E I G H T

Vitamin

Chick meal

Thiamine Riboflavin Nicotinic acid Vitamin A Vitamin E N.D.

0.4 21.0 98.0 N.D. N.D.

Non-detectable.

riboflavin, but a relatively poor source of thiamine. In addition, although no other vitamin analyses were performed on these samples, poultry and hatchery byproduct meals are also generally known to be good dietary sources of choline and vitamin B I 2 . It may be of particular nutritional interest to mention here that CM may contain traces of the protein avidin, which is a biotin antagonist, since this antivitamin factor is normally present within the yolk reserve of the yolk sac. While avidin can be destroyed by heat treatment, it is unlikely that the present method of drying CM would be sufficiently strong to destroy the avidin present (M. E. Putnam, personal communication). M i cr o b i a l content

A serious problem which may arise from the use of CM and CSM as a feed additive concerns the potential health hazards arising from the presence of viable microbial pathogens and parasites within the material. It is known that chick egg shells and hatchery waste by-products do carry a substantial burden of contaminating micro-organisms (Ichhponani & Lodhi, 1976). To eliminate the risk of disease transmission, therefore, it is essential that these products be processed in such a manner so as to ensure complete destruction of the disease-causing organisms, or to reduce their levels to the permitted standards for health and safety (Tacon, 1978/1979: 1979). CONCLUSION

Based on the foregoing proximate and biochemical criteria, CM can be described as an animal protein concentrate equivalent to 'meat meal'. Within the Fertilisers

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A. G . J . TACON

and Feeding Stuffs Regulations (HMSO, 1973) meat meal is defined as ' . . . t h e product, containing not less than 55 ~o of protein and not more than 4~o of salt, obtained by drying and grinding animal carcases or portions thereof (excluding hoof, horn and feathers) to which no other matter has been added but which may have been preliminarily treated for the removal of fat'. CM is a good source of protein, lipid, and the elements Ca, P, Fe, Cu, Ni and Cr. Despite this, however, there are a number of potential hazards which may be associated with the use of CM as an animal feed supplement. These may include difficulties associated with high lipid, cystine, Zn and Pb intake, unwanted carotenoid pigmentation, avidin and microbial contamination. It may be advisable that such a product be processed in such a way as to remove a large proportion of the lipid fraction (meat and bone renderers), cooked to ensure sterilisation and to hydrolyse the feathers, and finally dried to produce a product containing no more than 10 ~ moisture. CSM, on the other hand, can be described as a mineral-based product equivalent to trace element-enriched limestone or a phosphorus-deficient steamed bone meal. As such, within a commercial feed ration, CSM could be incorporated at low dietary levels as a valuable source of Ca, Mg, Cr and trace elements. For the potential of these products to be realised by the feed industry, it is imperative that adequate government incentives be supplied to the industry to introduce new forms of feed, and most importantly to develop suitable and economic processing technology.

ACKNOWLEDGEMENTS

The author would like to thank Mr H. Reed, Joice and Hill (Hisex) Ltd, South Raynham, Norfolk, who made the day-old chicks and chick egg shells available. Special thanks are due to Mr S. Howett for his assistance with amino acid analysis, and to Mr D. Balloch, Applied Hydrobiology Research Station, Checkley, Staffordshire for his assistance with atomic absorption spectrophotometry. I am especially indebted to Dr G.A. Garton, Rowett Research Institute, Bucksburn, Aberdeenshire who carried out the fatty acid determinations, and to Mr M.E. Putnam, Roche Products Limited, Dunstable, Bedfordshire who carried out the vitamin determinations. This research was completed with the financial assistance of Joice and Hill (Hisex) Ltd, at the Department of Biological Sciences, University of Aston in Birmingham, Birmingham.

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HAMBRID~3E, K. M. (1974). C h r o m i u m nutrition in man. Am. J. Clin. Nutr., 27, 505 14. H M S O (1973). The Fertilisers and Feeding Stuffs Regulations. H M S O No. 1521, London. HUMENIK, F. J., OVERCASH, M. R., SNEED, R. E. & BARKER, J. C. (1978). Hatchery waste management and utilisation by land application. J. Water Pollut. Control Fed., 50, 7 3 9 4 6 . I('HHPONANI,J. S~ & LODHI,G. N. (1976). Re-cycling animal waste as feed: A review. Indian J. Anita. Sci., 46(5), 234 43. McDONALD, P., EDWARDS, R. A. & GREENHALGH, J. F. D. (1976). In Animal Nutrition (2nd edition). Longman, London and New York. ME~TZ, W.,(1969). C h r o m i u m occurrence and function in biological systems, Physiol. Rev., 49, 163-239. ROACH, A. G., SANDERSON, P. & WILLIAMS, D. R. (1967). Comparison of methods for the determination of available lysine value in animal and vegetable protein sources. J. Sci. Fd Axric., 18, 274-8. SALEVSKY, E. & LEACH, R. M. (1980). Studies on the organic components of shell gland fluid and the hen's egg shell. Poultry Sci., 59(2), 438-43. TACON, A. G. J. (1978/1979). Activated sewage sludge, a potential animal foodstuff, II. Nutritional characteristics. Agric. Environm., 4, 271-9. TACON, A. G. J. (1979). Nutritional evaluation of animal and food processing wastes. Presented at Third International Conference on Effluent Treatment in the Biochemical Industries, 7th November, London. TACON, A. G. J. & FERNS, P. N. (1978/1979). Activated sewage sludge, a potential animal foodstuff, 1. Proximate and mineral content: seasonal variation. Agric. Environm., 4, 2 5 7 69. UNDERWOOD, E J. (1971). In Trace Elements in Human and Animal Nutrition (3rd edition). Academic Press, New York and London. VANDEPOPULIERE,J. M., KANUNGO, H. K., WALTON, H. V. & C01TERILL,O. J. (1977). Broiler and egg type chick hatchery by-product meal evaluated as laying hen feedstuffs. Pouhry Sci., 56, 1140 4.