Effect of selected supplemental feed additives on production performance and liver histology of laying chickens fed mouldy diets
The studydetermined the effect of dietary supplemental retinol, tocopherol, a multi-vitamin and a commercial adsorbent on the production performance and liver histology of laying chickens fed mouldy diets and assessed the toxicity of mouldy diets on liver of birds with a view to ameliorate the toxic effects of mould contamination in feed for laying chickens. The experimental birds were completely randomized into six treatments in three replicates of 10 birds each. The control group was fed Aflasafe maize diet while birds in treatments two were fed mouldy maize diets without supplement, treatment three were fed mouldy maize diet supplemented with retinol, treatment four were fed mouldy maize supplemented with tocopherol, treatment five were fed mouldy maize supplemented with a multi-vitamins (vitalyte) while treatment six were fed mouldy maize diet supplemented with a commercial adsorbent (activated charcoal) supplement respectively. Results of chemical composition of test samples showed that crude protein and crude fat reduced by 11.54% and 12.72% respectively in the mouldy maize, crude fibre content was higher by 31.7% in the mouldy maize and there was a substantial depreciation in both retinol and tocopherol contents of the mouldy maize and diets compared to the control. Similarly the aflatoxin content rose from near zero in aflasafe maize grains to 267µg in mouldy maize and from 0.78µg in aflasafe diet to 118µg in the mouldy diet. In terms of performance, the control group had higher (P<0.05) body weight gains, hen day production, feed conversion efficiency and the highest feed cost/kg egg. The vitamins supplemented groups were similar (P>0.05) to the control in terms of performance except for their lower feed cost/kg egg with treatment three having the lowest feed cost/kg egg among the additive supplemented groups. Egg quality differs (P<0.05) only in terms of shell thickness, shell weight and yolk colour. The commercial adsorbent had superior values (P>0.05) over vitamin supplements in term of shell thickness and compare more closely with the control while significantly low values (P<0.05) were obtained for birds on mouldy non- supplemented diet. Liver histology photomicrographs showed that supplementation with vitamins showed some ameliorative tendencies of aflatoxicosis as evidenced by essentially normal architecture of the hepatocytes particularly in the multi- vitamin supplemented group which was quite similar to the aflasafe control. Cellular infiltration, congestion, and hypercellularity or dilation of the sinuosoidal spaces characterized liver of bird fed on mouldy diets. The study concluded that feeding mouldy diets supplemented with retinol, tocopherol and vitalyte is safe for poultry birds although mouldy feed should be prevented as much as possible in layer chicken production.