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Die Bodenkultur - Journal for Land Management, Food and Environment
B. Hassanpour, W. Zollitsch and F. Lettner:
The use of raw full-fat soybeans in rations for laying hens
The effect of the use of 10 % raw full-fat soybeans in rations for laying hens with different dietary crude protein content was investigated.
In 2 experimental periods there were 2 groups, a control group which was fed a commercial layer diet with soybean meal as the main protein source and an experimental group. In the ration of the experimental group, a proportion of the soybean meal, wheat bran and fat were substituted by 10 % full-fat soybeans.
Each group consisted of 1000 hens which were 26 weeks of age and were kept in battery cages. Duration of the first experimental period was 5 and of the second period 3 months. Laying performance, egg quality and the composition of the faeces were investigated.
In the second experimental period dietary crude protein content was reduced from 17,8 % to 14,8 % and there was a supplementation of 0,10 % methionine and 0,15 % lysine. All the diets were processed by expanding, and the contents of trypsin inhibitors were analyzed.
The most important results from both experimental periods were:
- The dietary content of trypsin inhibitors for the experimental group (4,38 TIU/mg) was about 5 times higher than for the control group.
- The laying performance of the experimental group (91,9 %) was about 1,1 % significantly higher than for the control group. In the whole experiment there were no differences in the egg weight.
- Pancreas weight was higher for hens fed 10 % full-fat soybeans.
- The diet had no consistent effect on egg quality characteristics.
- In both experimental periods the fatty acid pattern of the eggs was typically affected by feeding 10 % full-fat soybeans: the content of saturated and single-unsaturated fatty acids decreased whereas the percentage of linoleic and linolenic acid was increased.
From the results it can be concluded that soybean meal can successfully be replaced by full-fat soybeans. Reduction of dietary crude protein content also resulted in a 16.8 % decrease of N excretion by the hens.
Key words: laying hens, soybean, pancreas, fatty acids.