Nutritional evaluation of grain amaranth (Amaranthus hypochondriacus) in broiler diets

The present study was conducted to evaluate the feeding and energy utilization values of raw and autoclaved grain amaranth (Amaranthus hypochondriacus) in broiler diets. The grain amaranth sample used in the study contained (g kg−1): crude protein, 168; crude fat, 58; crude fibre, 60; ash, 26; calcium, 2.2; total phosphorus, 5.6; lysine, 10.1; methionine, 3.5. al 1, raw amaranth was incorporated into a maize-soyabean meal-meat meal diet at 0, 200, 400 and 600 g kg−1 levels and fed to broiler chicks from 7 to 16 days of age. Weight gains and feed intake were depressed (P < 0.01) with increasing levels of raw amaranth in the diet. Feed/gain values were similar between birds fed on diets containing 0 and 200 g kg−1 amaranth, but increased (P < 0.01) beyond 200 g kg−1 level of inclusion. Trial 2 was conducted to evaluate whether the growth-depressing effects of raw amaranth grain could be overcome by autoclaving (130°C for 1 h). Weight gains, feed intake and feed/gain of chicks fed on 200 and 400 g kg−1 autoclaved amaranth diets were similar (P > 0.05) to those fed on the control diet. The apparent metabolizable energy (AME) of grain amaranth was improved by autoclaving. The AME (MJ kg−1 DM) values of raw and autoclaved amaranth were 11.85 ± 0.29 and 13.11 ± 0.26, respectively. The positive responses to autoclaving, in terms of feeding and energy utilization values, suggest the presence of heat-labile anti-nutritional factor(s) in raw amaranth and studies are warranted to identify these factors. The results indicate that processed A. hypochondriacus grain is a potentially useful energy supplement for poultry and can be incorporated in broiler diets at levels up to 400 g kg−1 without adverse effects on performance.