The evaluation of Brewers Dried Grains (BDG) in poultry rations 1. Breeder chicken rations

R. Fombad and J. Mafeni
Institute of Animal Research
Mankon, Bamenda, Cameroon

Abstract
Introduction
Materials and methods
Results and discussion
Conclusion
Acknowledgements
References

Abstract

In an attempt to establish the optimum level of brewers dried grains (BDG) from a Cameroonian brewery that can be incorporated in breeder rations without adverse effect on productive performance, a study was carried out with 120 laying hens and 12 cocks of Isa Commercial breed. A complete randomised design was utilised in which the dietary treatments contained 0, 10, 20, and 30% levels of BDG was fed. Feed and water were provided ad libitum over the 5-month experimental period. Parameters such as egg production, egg weight, feed intake, albumen height, egg shell weight, semen quantity, fertility and hatchability of fertile eggs were measured.

Results showed that when BDG was fed at 30% level in the ration, the hen-day production (50.6%) was significantly (P<0.05) depressed than when the 0% level (56.2%), 10% level (56.9%) and 20% level (56.7%) were fed. There was a significant increase in egg weight with the increased level of BDG in the ration. Also the feed intake per bird per day was significantly (P<0.05) and progressively increased with increasing levels of BDG. No significant difference was noticed between treatments for ratio of shell weight to egg weight, albumen height and semen quantity for birds fed the 0,10,20 and 30% levels of BDG. Although the amount of feed to produce a dozen eggs increased significantly (P<0.05) as the level of BDG increased in the diet, it was noticed that the cost of feed required to produce a kilogram of eggs was progressively reduced as the level of BDG increased in the ration viz 455, 420, 406, 401 CFA (1US$ = 295CFA) for 0,10, 20 and 30% levels respectively. It would appear that the 30% level of BDG can be tolerated but the 20% level of BDG was most appropriate for breeder birds.

Constraints on the use of this by-product include bulkiness of the wet grains, drying procedure and its high fibre content.

Introduction

In Cameroon, one of the limitations to the expansion of the poultry industry is the high cost of protein and energy ingredients such as fish meal, decorticated cottonseed cake, maize and guinea corn. In order to reduce this high cost, efforts are being directed to the use of non-conventional feed ingredients. Brewers dried grains (BDG) a by-product of the beer industry might offer a suitable cheap substitute. Despite the increasing number of brewers in Cameroon, knowledge about the use of brewery by-products is almost non-existent. The problem facing most of the breweries is that of disposing the wet grains. Current disposal practices include free donations of wet grains to any interested persons staying within the 25 km radius from the brewery or payment of contractors by the breweries to collect and dump the bulky daily output of the wet grains. Currently the wet grains are used as manure, and a few farmers in the Western province feed it to pigs.

BDG however contains a wide variety of essential nutrients which are required in feed formulation for poultry. Couch (1978) and Ewing (1965) analysed some BDG samples and found that it contained over 20% crude protein, about 6% ether extract, over 15% crude fibre and about 4% ash. Almquist (1972) found that BDG contained 25% crude protein and that it was fairly rich in essential amino acids i.e. 0.9% lysine, 0.4% methionine, 0.4% tryptophane, 1.2% phenylalanine, 1.1% threonine and 1.6% valine. It is therefore higher in protein and amino acids than corn. Its use as animal feed does not call for competition between man and livestock as in the case of corn and other ingredients.

The use of BDG in poultry feed would not be without constraints. The product is collected with moisture content of about 80% which increases its bulkiness. It needs to be dried before incorporation in poultry rations. Sun-drying is the most common method used and this method requires large space and large polythene sheets for drying. During drying the wet grains have to be spread in a thin layer and frequently turned to avoid fermentation which could result in lowering the nutritive value of the by-product. The turning process is tedious and time consuming. The present study was conducted to evaluate the use of BDG in breeder poultry rations.

Materials and methods

A total of 120 laying hens and 12 cocks of Isa Commercial breed were used in this trial. The layers which had been in lay for 120 days were randomly divided into four equal treatment groups of 30 birds each and these were further divided into five replicate groups of 6 birds each. The cocks were divided into four dietary groups of 3 cocks each. The hens and cocks were placed in cages in pairs and singly, respectively. The wet grains were collected from Baffoussam, 90 km from Mankon Station and sun-dried for 72 hours on black polythene paper and stored in jute bags. Before the BDG and corn were used in the formulation of the rations, a sample of each was analysed for proximate composition and amino acid profile (Table 1a and 1b).

Table 1a. Proximate composition of brewers dried grains and corn (dry-matter basis).

Ingredient	Brewers dried grains	Corn
Crude protein (%)	27.7	9.1
Crude fibre (%)	15.7	2.9
Ether extract (%)	7.2	4.3
Ash (%)	3.8	1.2

Table 1b. Amino-acid composition of BDG and corn Used in the rations.

Feedstuffs	Amino-acid composition (%)
	Arginine	Cystine	Histidine	Isoleucine	Leucine	Lysine	Methionine	Phenylanine	Threonine	Tryptophan	Tyrosine	Valine
Corn (yellow)	0.45	0.09	0.18	0.45	0.99	0.18	0.09	0.45	0.36	0.09	-	0.36
Brewers dried grain	1.30	-	0.50	1.50	2.30	0.90	0.40	1.30	0.90	0.40	1.20	1.60

A complete randomised design was utilised in which the four dietary treatments (Table 2) containing 0, 10, 20 and 30% levels of BDG were fed. In the formulation of the diets, the other ingredients were adjusted to maintain isoprotein, energy, calcium and phosphorus levels as BDG was increased. Palm oil was used to balance the energy levels.

The birds were transferred to their cages and left for a week to adjust to the cage environment; within which period they were fed a normal layer diet without BDG. Thereafter, birds were fed for a week the experimental diet before data collection started. Feed and water were provided ad Librium and record for feed consumption was kept. Eggs were collected daily and records of daily egg production and egg weight for all replicate groups were kept through the five months duration of the trial. Average hen-day production was calculated. Two eggs from each replicate group were taken daily at random, weighed, broken and albumen height was measured as an indication for egg quality (using a Haugh Unit gauge). The egg shells from the broken eggs were washed and dried in an oven at 60°C overnight and weighed. The egg shell was expressed as a percentage of the egg weight.

Semen were collected from the cocks by the massage technique (Quin and Barrou, 1937). The semen quantity from each cock was measured, then the semen from the same dietary group was pooled and inseminated to the corresponding hens offered the same diet. Approximately 0.1 ml of whole semen (estimated to contain 8x10⁸ spermatozoa, Yousif et al, 1984) was inseminated into each hen. The artificial insemination was done usually in the evenings, at about 4.00 p.m. when it was assumed that the hens have laid and it was repeated at intervals of 7 days.

Table 2. Composition of experimental rations.

Ingredient	% level of BDG
	0	10	20	30
Corn (yellow)	63.5	57.5	49.5	42.3
BDG	0	10.0	20.0	30.0
Cottonseed cake	17.5	13.0	9.0	4.7
Fish meal	5.6	5.6	5.6	5.6
Palm oil	2.1	3.1	5.1	6.7
Bone meal	3.0	3.0	3.0	3.0
Calcium carbonate	7.1	6.6	6.6	6.5
L-Lysine	0.2	0.2	0.2	0.2
Layer concentrate	0.5	0.5	0.5	0.5
Salt	0.5	0.5	0.5	0.5
Total (kg)	100	100	100	100
Analysis (dry-matter basis)
Crude protein (%)	17.8	17.7	17.7	17.8
Crude fibre (%)	3.5	4.4	5.3	6.2
ME (kcal/kg), calculated	2949.9	2931.3	2931.3	129295
Calcium (%)	4.4	4.5	4.5	4.4
Phosphorus, total (%)	0.781	0.77	0.77	0.75

SADE (Cameroon) layer concentrate supplied per kg the following:

Vitamin A 9000 IU; vitamin D₃ 1800 IU; vitamin E 14.4 mg;

Vitamin K 1.4 mg; vitamin B₁ 1.0 mg; vitamin B₂ 4.1 mg;

Vitamin PP 18 mg; calcium patothenate 9 mg; vitamin B6 1.8 mg;

Vitamin B₁₂ 0.02 mg; folic acid 0.7 ma; biotin 0.06 ma; choline chloride 300 ma; BHT antioxidant 120 mg.

The eggs from each dietary group were marked after collection, identification and stored in a cool room (18°C) for two weeks before incubation. On the seventh day of incubation the fertile eggs were detected by candling the eggs using a locally made candler. The hatchability was calculated by the number of fertile eggs.

The different rations were analysed for their proximate analysis using methods outlined by A.O.A.C. (1975). Data collected were subjected to statistical analysis (Steel and Torrie, 1980) and significant means were tested according to Duncan's Multiple Range Test (Duncan, 1958).

Results and discussion

The results on the laying performance (Table 3) show that feeding up to 20% of BDG did not significantly affect the hen-day production. However, the laying performance was significantly (P<0.05) depressed when the ration containing 30% BDG was fed. The average hen-day production percentages for the 0, 10, 20, and 30% levels of BDG were 56.20, 56.88, 56.65, and 50.59, respectively. These results are contrary to the findings of Onwudike (1981) who reported that the laying performance was not significantly affected when BDG was fed up to 40%. Although the amino acid levels of diets were increasing as the BDG levels in the rations increased, the fall in egg production at 30% levels of BDG in the ration may be caused by high crude fibre level of the ration at this level.

Table 3. Calculated amino acid composition of experimental diets.

	Level of BDG (%) in the rations
Amino acid	0	10	20	30
Arginine	1.25	1.12	1.09	1.04
Cystine	0.26	0.48	0.49	0.48
Histidine	0.45	0.40	0.38	0.37
Isoleucine	0.79	0.85	0.90	0.94
Leucine	1.75	1.90	2-03	2.14
Lysine	0.96	0.95	0.96	0.96
Methionine	0.27	0.28	0.33	0.38
Phenylalanine	0.87	0.85	0.82	0.80
Threonine	0.65	0.65	0.65	0.66
Tryptophan	0.21	0.21	0.22	0.23
Tryrosine	0.09	0.21	0.33	0.45
Valine	0.79	0.84	0.88	0.93

The egg weight progressively increased with the level of the BDG in the rations. Birds fed the ration containing 10% level of BDG laid significantly (P<0.05) larger eggs than those on the control ration (62.30 versus 60.76 g respectively). Also feeding 30% level of BDG significantly (P<0.05) increased the egg weight (63.95 g) as compared to (62.30 g) in the ration containing 10% level of BDG. There was, however, no significant difference in egg weight for birds fed the 20 and 30% levels of BDG. The improved egg size may be due to the increase of amino acid pattern (Table 4) caused by increased BDG levels in the rations which may increase the egg protein synthesis and hence larger egg sizes. This could be in part as a result of higher linoleic acid level which correspond to higher BDG levels. Bragg quoted by North (1972) stated that increasing the linoleic acid in chicken diets could raise the deposition of polyunsaturated fatty acids in the egg yolk from a basic level of about 5% to approximately 28%. The average feed intake per bird per day significantly (P<0.05) increased with increasing levels of BOG. The average feed intake for the 0, 10, 20 and 30% levels of BOG were 100.71, 111.69, 122.97 and 130.51 g respectively. This same trend was noticed by Owudike (1981). The trend in feed intake could not be related to the energy levels of the rations since the rations were about iso caloric. One of the possible reasons for this difference in intake could be the greater tendency for the birds to spill the feed in search of grains when higher levels of BDG were fed.

There were no significant differences noticed between treatments for the ratio of shell weight to egg weight, albumen height and semen quantity for birds fed the 0, 10, 20 and 30% levels of BOG. The egg shell did not then contribute to the difference in egg weight. The various levels of BDG did not also affect the quantity of semen produced by the cocks. Although the fertility percentage increased with increased levels of BDG in the rations (Table 4) this increase was not significantly different between dietary treatments. The percentage hatch of fertile eggs increased by the increase in the level of BDG in the diets. The hatchability for fertile eggs from birds fed BDG was significantly (P<0.05) greater than those of the control group (Table 4).

Table 4. Effect of feeding brewer dried grain on breeder chickens performance.

Traits	Levels of BDG (%)
	0	10	20	30	± SEM+
Av. hen-day production (%)	56.20a	56.88a	56.65a	50.59b	1.33*
Av. egg weight (g)	60.76c	62.30b	62.51ab	63.95a	0.42*
Av. feed intake/bird/day (g)	100.71d	111.69c	122.97b	13051a	167*
Ratio of shell weight: egg weight (%)	9.59	9.87	9.88	9.40	0.210ns
Albumen height (haught unit)	101.68	101.15	102.39	104.87	1.109ns
Semen quantity/cock (ml)	1.41	1.01	1.05	1.13	0.153ns
Fertility (%)	58.51	59.33	58.81	58.94	1.23ns
Hatch of fertile eggs (%)	67.20c	75.84b	80.93a	81.32a	130*

Means with the same superscript are not significantly different at (P<0.05).

* = significant differences among treatment means (P<0.05). ns = no significant differences.

SEM = standard errors of means.

However, the hatchability for the 20 and 30% levels of BDG in the rations was significantly (P<0.05) greater than those of 10% levels of BDG (80.93, 81.32 versus 75.84%, respectively). Kienholtz and Jones (1967) attributed this improved fertility and hatchability of fertile eggs to an unidentified factor in BDG.

A view of the economic analysis of feeding (Table 5) shows that feeding above 20% level of BDG significantly (P<0.05) increased the amount of feed required to produce a dozen eggs. It was also noticed that the cost of feed required to produce a kilogram of eggs was progressively reduced for 0, 10, 20 and 30% levels of BDG in the rations. The cost was 455, 420, 407, 401 CFA respectively. This reduction in price with increase in the level of BDG was a result of the fact that BDG cost was less than corn, 40 vs 100 FCFA a kg, respectively.

Table 5. Economic analysis of feeding BDG to breeder birds.

Economic analysis	Levels of BDG (%)
	0	10	20	30	±SEM
Cost/100 kg of ration (CFA)¹	15,698	15,013	14,529	13,982
Cost of feed/dozen eggs (CFA)	315	328	393	479
Cost of feed/kg eggs (CFA)	455	420	406	401
Kg feed/dozen eggs ² (kg)	2.01b	2.19b	3.04a	3.43a	0.065

Means with the same superscript are not significantly different at (P<0.05).

¹ 295 CFA is equivalent to 1 US dollar.
² Only the kg feed/dozen eggs was analysed statistically.

Conclusion

The results showed that 30% level of BDG can be tolerated in layer diets but 20% level of BDG in the rations would be the most appropriate level for breeder birds. With the high fermentation properties of the wet grains drying should be done only in the dry season and it is hoped that drying houses would be designed to dry the wet grains in the rainy season. This is to assure an all year round dried grains that would not stand the risk of contamination as a result of long storages.

The major limitation to the use of this byproduct in poultry rations was its high fibre content. The high fibre content resulted in lower digestibility of the rations containing high amounts of BDG.

Acknowledgements

The authors acknowledge with thanks the Ministry of Higher Education and Scientific Research (MESRES) for the funds that supported this study and Dr. R T Fomunyam for her useful suggestions. The technical assistance of Mrs. E. Forchap and L. Ngassa is also appreciated.

References

Almquist, H.J. 1972. Protein and amino acids in animal nutrition. S.B. Penick and Co., New York.

AOAC (Association of Official Analytical Chemists). 1975. Official methods of analysis. 12th ed. AOAC, Washington, D.C.

Couch, J.R. 1978. Brewers dried grains in poultry feed. Poultry International, July, 42.

Duncan, D.B. 1958 Multiple Range and Multiple F. tests. Biometrics 1: 1-42.

Ewing, W.R. 1965. Poultry nutrition. 5th ed, Pasadena, Ray Ewing Co., Pasadena, California. pp. 396-418.

Kienholtz, E. W. and Jone, M.L. 1967. The effect of brewers dried grains in some poultry rations. Poultry Sci. 46: 1280.

North, M.O. 1972. Commercial chicken production manual. The Avi Publishing Co. Inc., West Port, Connecticut. 454 pp.

Onwudike, O.C. 1981. The use of brewers dried grains by laying hens. Nutr. Rep. Int. 24 (5): 1009.

Quin, J.P. and Barrows, W.H. 1937. Collection of spermatozoa from domestic fowl and turkey. Poultry Sci. 16: 19 24.

Steel, R.G.D. and Torrie, J.H. 1980. Principles and procedures of statistics. McGraw-Hill Book Company, N.Y.

Yousif, Y.F; Ansaband, G.A. and Buckland, R.B. 1984. Effect of selection for fertility of fresh and stored semen. Poultry Sci. 63: 1475-1480.