The effects of a partial or total replacement of ground corn with ground and whole-grain low-tannin sorghum (Sorghum bicolor (L.) Moench) on zootechnical performance, carcass traits and apparent ileal amino acid digestibility of broiler chickens

Abstract

The partial (50%) or total (100%) replacement of corn in broiler diets with a home-grown sorghum cultivar low in tannins was investigated regarding the effects on zootechnical performance, apparent ileal nutrient digestibility (AID) and carcass traits. A total of 240 mix-sexed Ross 308 broilers were randomly assigned to four experimental diets: 100% corn (M), partial replacement of corn with 50% ground sorghum (S50G), total replacement of corn with ground sorghum (S100G) and a total replacement of corn with 50% ground + 50% whole grain sorghum (S100/50WG). All final feed mixtures were calculated isoenergetic as well as isonitrogenous and met or exceeded current feeding recommendations. Analyses included body weight (BW), average daily weight gain (ADWG), average daily feed intake (ADFI) and feed conversion ratio (FCR) during the complete experimental period of 29 days. In the end, broilers were slaughtered and carcass traits as well as AID of amino acids (AA) and crude nutrients were determined. The results demonstrated that partial or total replacement of corn by home-grown low-tannin sorghum is suitable for broiler chicken diets with no adverse effects on zootechnical and slaughter performance over the whole trial period. A numerical decrease of AID in dry matter (DM), crude ash (CA), methionine and tyrosine were observed in experimental groups with sorghum compared to M. The partial and total replacement of corn with ground or whole grain sorghum had no significant effect on carcass weight, dressing, or absolute and relative weight of carcass parts. Broiler chickens expressed increased absolute and relative proportion of the gizzard weight (p ≤ 0.05) due to the increase in particle size in S100/50WG. Total replacement of corn by sorghum reduced lightness, redness and yellowness of abdominal fat in comparison to M (p ≤ 0.05). It can be concluded that home-grown low-tannin sorghum is suitable to create diets for the purpose of poultry meat production. The partial or total replacement of corn by ground or whole grain low-tannin sorghum in broiler diets did not influence the zootechnical or slaughter performance parameters in broiler chickens when the nutrients were balanced. However, the substitution of corn by sorghum negatively affected the coloring of the abdominal fat which requires an adequate dietary supplementation with pigments.