Economical poultry production is possible if balanced and cost-effective rations are formulated. In poultry production, the feed cost can go upto 77% of the total production expenses.
The major components of poultry rations are energy and protein. Protein is needed for body maintenance, growth, and reproduction. Protein sources are of two types i.e. animal protein and vegetable protein. The superiority of animal protein over vegetable protein is established due to its better profile of amino acids. Presently high cost and scarcity of animal protein sources as well as the unscientific methods of their preparation suggest limiting their use in poultry feeds. Vegetable protein is generally supplied through different cereals, their by-products, and cakes/meals of oil seeds.
The shortage of feed ingredients always provokes animal nutritionists to explore the actual nutritional potential of newly available feed resources that have been either neglected or exploited inadequately. A by-product of corn wet milling i.e. corn steep liquor (CSL) is also one such product that has been neglected or inadequately exploited. It is a vegetable protein source that is available at a reasonable price. Besides its high protein and medium energy contents corn steep liquor can be used as a protein source in poultry feed. Simultaneously it can provide some vitamins and minerals to the chicken.
It contains about 23% crude protein and 1558kcal/kg metabolizable energy on such a basis (Product Reference Guide, CPC.Rafhan, 1997). It is a good source of unidentified growth factor (UGF) for chicken. Tsang and Schaible, (1960) indicated that corn fermentation solubles(CFS) contained an unidentified growth factor for chicks. Potter and Shelton, (1978) suggested that CFS contained an unidentified growth factor for turkey poults. Corn-dried steep liquor concentrate may be used in the diet at levels up to 15% in a nutritionally balanced broiler diet.
The production of corn (maize) as well as its processing industries in the country is increasing. Fairly large amounts of corn-steep liquor will therefore be available in the market in the near future. Easy availability, fairly low price, and good source of nutrients are the compelling reasons for making use of this ingredient in poultry rations.
The effect of substitution of soybean meal with corn steep liquor (dried) in broiler rations was studiied. One hundred and eighty, day-old broiler chicks were reared up to 6 weeks of age. Four experimental rations A, B, C, and D containing 17.50, 14.0, 10.25 and 6.50% soybean meal with 0, 4, 8, and 12% corn steep liquor(dried) respectively. Average weight gain was 2010, 2008.3, 1848 and 1814gms and feed consumption up to 6 weeks was 3775.66, 3531.33, 3605.33 and 3619.66gms in chicks fed on ration A, B, C and D.
The procedure of making CSL
Corn steep liquor (CSL) is obtained through the wet milling of corn. This process also makes valuable use of each constitute of the corn kernel. In addition to starch and the various products derived from it, along with highly valued oil from the germ, 25 to 30% of the corn used by the wet milling industry goes into the production of live stock feeds .
Before storage, shelled corn is initially cleaned to remove extraneous material such as pieces of corn cob, foreign seeds, stray metal, fine dirt, or unwanted material. When the corn is taken from storage, it is cleaned again and steeped in series of tanks where, after regular intervals a solution of sulfurous acid water is recalculated. This procedure which takes any where from 24 to 48 hours, disintegrates the protein that binds the starch with the kernel , thereby softening the kernel and facilitating grinding . The steep water which is removed from this process contain about 6% solids, of which about 35% to 45% consist of protein . The steep water then undergoes evaporation, whereupon the level is reduced to 45 to 65% . This high extract may be used as a nutrient for micro-organisms in the production of enzymes, antibiotics, and other fermentation products. The major protein, however, is combined with fibre and gluten in the production of animal feed ingredients .
After steeping , the extracted corn is degermed by coarse grinding , yielding a pulpy material which contain the germ, hull, starch, and gluten . This material is then passed through a liquid cyclone which separates the germ from the rest of the material. Oil is extracted from the germ through, hydraulic, expeller, or solvent process. The extracted germ is dried and sold as corn germ meal for animal feed .
Following the separation of the germ, the remaining materials containing starch, hulls. And gluten pass through a series of screens which separates the various fractions from starch.
The water slurry of starch and gluten is separated by centrifugation . Typical operations yield a gluten stream containing over 60% protein. The gluten is dried and sold as gluten meal (60%) or it may be used as an ingredient in corn gluten feed (21% protein) .
After treatment the products are recovered by filtration or centrifugation and the starch is dried. Thus wet milling of corn produces major feed ingredients, corn gluten feed corn gluten meal and condensed fermented corn extractives or corn steep liquor .
Experiment with Birds
One hundred and twenty-day-old Hubbard broiler chicks were ring banded for identification and randomly divided into 12 experimental units of 10 chicks each which were kept in separate pens. They were fed experimental starter rations from day old to the end of fourth week and after that they were shifted to experimental finisher rations for a period of two weeks. These chicks were reared under standard managemental conditions.
Starter Ration
Four iso caloric and iso nitrogenous experimental broiler starter rations i.e A, B, C and D were formulated according to the NRC recommendations. The ingredients and nutrients composition of the experimental starter rations is given in table 1. The rations contained 23% crude protein and 3000kcal/kg metabolizable energy. Ration A containing 4% molasses served as control ration while rations B, C and D were contain 2, 4 and 6% corn steep liquor with no molasses(Table 1). The protein content supplied through the addition of various levels of corn steep liquor were proportionately subtracted through reducing soybean meal.
Finisher Ration
Four iso caloric and iso nitrogenous experimental broiler finisher rations i.e A’, B’, C’ and D’ were also formulated according to the NRC recommendations Ration A’ containing 4% molasses served as control ration while rations B’, C’ and D’ were contain 2, 4 and 6% corn steep liquor with no molasses. The ingredients and nutrients composition of the experimental finisher rations is given in table 2. The rations contained 20% crude protein and 3000kcal/kg metabolizable energy. The protein contents supplied through the addition of various levels of corn steep liquor were proportionately subtracted through reducing soybean meal.
The experiment was conducted in to two phases. In phase 1 one hundred and twenty day old broiler chicks were randomly divided into 12 experimental units of 10 chicks each. Each experimental starter ration were fed to 3 experimental units for a period of 4 weeks. These rations were fed from day old to the end of 4th week.
During 2nd phase(finisher) the birds previously fed on respective starter rations were shifted to respective finisher ration. These rations offered to the birds from the end of 4th week to the end of 6th week. Feed and water were offered to the birds ad-libitum through out the experimental period.
Starter Ration
Four iso caloric and iso nitrogenous experimental broiler starter rations i.e A, B, C and D were formulated according to the NRC recommendations. The ingredients and nutrients composition of the experimental starter rations is given in table 1. The rations contained 23% crude protein and 3000kcal/kg metabolizable energy. Ration A containing 4% molasses served as control ration while rations B, C and D were contain 2, 4 and 6% corn steep liquor with no molasses(Table 1). The protein content supplied through the addition of various levels of corn steep liquor were proportionately subtracted through reducing soybean meal.
Finisher Ration
Four iso caloric and iso nitrogenous experimental broiler finisher rations i.e A’, B’, C’ and D’ were also formulated according to the NRC recommendations Ration A’ containing 4% molasses served as control ration while rations B’, C’ and D’ were contain 2, 4 and 6% corn steep liquor with no molasses. The ingredients and nutrients composition of the experimental finisher rations is given in table 2. The rations contained 20% crude protein and 3000kcal/kg metabolizable energy. The protein contents supplied through the addition of various levels of corn steep liquor were proportionately subtracted through reducing soybean meal.
The experiment was conducted in to two phases. In phase 1 one hundred and twenty day old broiler chicks were randomly divided into 12 experimental units of 10 chicks each. Each experimental starter ration were fed to 3 experimental units for a period of 4 weeks. These rations were fed from day old to the end of 4th week.
During 2nd phase(finisher) the birds previously fed on respective starter rations were shifted to respective finisher ration. These rations offered to the birds from the end of 4th week to the end of 6th week. Feed and water were offered to the birds ad-libitum through out the experimental period.
Cumulative ( 0-6 weeks)
At the end of the experiment the over all feed efficiency values in case of chicks fed experimental starter cum finisher rations were 2. 05, 2. 02, 1. 87 and 1. 89 (Table 12). The data when subjected to analysis of variance showed highly significant differences (P< 0.05) among the feed efficiency values of group C/C’(4% CSL) as compared to control group A/A’(4% molasses) (Table 6). When the DMR test was applied the highly significant differences (P<0.05) in feed efficiency values was observed in ration C’ ( 4% corn steep liquor) as compared to ration A’ (4% molasses). However significant difference (P<0.05) in groups A/A’, B/B’, and D/D’ containing 4% molasses, and 2% & 6% corn steep liquor (CSL) respectively were also noticed.
Best feed efficiency 1.87 was observed in chicks fed on ration C/C’ (4% CSL) while poor feed efficiency 2.05 was noticed with ration A/A’ (4% molasses).
Camp et al. (1958) observed that feed conversion was not markedly effected when 3% corn steep liquor and 3% dried whey (combined) were used.
Russo et al. (1960) reported that when 5% corn fermentation condensed solubles were added to the fish less ration, feed efficiency was improved. The above findings are in agreement with the findings of the present study that use of corn steep liquor improved the feed efficiency.
Simon et al. (1960) reported that feed efficiency was improved when corn fermentation soluble supplemented with trace minerals.
Russo et al. (1960) observed that when fish soluble and dried whey products removed from the Animal Nutrition Research Council (A.N.R.C.) reference diet has small but significant depressing effect on feed efficiency, where as addition of 5% corn fermentation condensed soluble restored the feed efficiency.
Mazhar K. (1995) reported that better feed efficiency was noticed in group of chicks fed on ration containing 4% corn steep liquor (dried). The above mentioned results are in line with the results of the present study.
Binding ability
Starter phase (0-4 weeks)
The average daily refusal were 273.5, 260.4, 253.3 and 244.9 gm of the birds fed on starter rations A, B, C and D respectively (Table 18). The maximum refusal were obtained from A group fed on their respective ration A ( containing 4% molasses) and minimum feed refusal was obtained from D group fed on their respective ration D (containing 6% corn steep liquor). When the data was subjected to analysis of variance (Table 19) it revealed significant differences (P<0.05) among feed refusal values of the chicks fed on control ration A (4% molasses) and (treatment) ration D containing 6 % corn steep liquor.
DMR test was applied to compared the mean values of control and treatment rations (Table 18). It showed that there were significant difference (P< 0.05) between the mean value of ration A (4% molasses) and ration D (6% corn steep liquor).
Finisher phase (5-6 weeks)
The average daily refusal were, 156.6, 144.3, 137.8 and 119.1gm of the birds fed on ration A’ (4% molasses), B’ (2% corn steep liquor), C’ (4%corn steep liquor), and D’ (6% corn steep liquor) respectively (Table 18). The maximum refusal were obtained from group A’ fed on their respective ration A’ ( containing 4% molasses) and minimum feed refusal was obtained from group D’ fed on their respective ration D’ (containing 6% corn steep liquor). When the data was subjected to analysis of variance (Table 20) it showed significant difference (P<0.05) among feed refusal values of the chicks fed on control ration A’ (4% molasses) and (treatment) ration D’ containing 6 % corn steep liquor.
DMR test was applied to compared the mean values of control and treatment rations (Table 18). It showed that there were significant difference (P< 0.05) between the mean value of ration A’ (4% molasses) and ration D’ (6% corn steep liquor). However non significant differences were observed among the mean values of ration B’ and C’ (Table 18) .
Cumulative (0-6 weeks)
At the end of the experiment total feed refusal of the chicks fed on rations A/ A’ (4% molasses), B/ B’ (2% corn steep liquor), C/C’(4%corn steep liquor), and D/D’ (6% corn steep liquor) were 430.1, 404.7, 391.1and 363.9 gm respectively (Table 18). The maximum refusal (430.1) were obtained from group A/A’ fed on their respective ration A/A’ ( containing 4% molasses) and minimum feed (363.9) refusal was obtained from group D/D’ fed on their respective ration D/D’ (containing 6% corn steep liquor). When the data was subjected to analysis of variance (Table 21) it showed significant difference (P<0.05) among feed refusal values of the chicks fed on different experimental ration.
For further comparison of means DMR test was applied (Table 18). It showed that there were significant difference (P< 0.05) between the mean value of ration A/A’ (4% molasses) and ration D/D’ (6% corn steep liquor).
Results indicated that the birds fed on ration D/D’ (6% corn steep liquor) consumed more feed as compared to other groups. It is concluded that D/D’ ration had better binding ability or efficiently agglomerate the feed particles which made it easy to pick the feed efficiently and ultimately improved the feed consumption
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