Nutrient Digestibility, Growth Performance, and Blood Indices of Boschveld Chickens Fed Seaweed-Containing Diets

SIMPLE SUMMARY: Sustainable intensification of indigenous chicken strains is largely constrained by the high cost of feed ingredients, thus limiting the growth of the poultry industry in developing countries. Inexpensive and readily available feed ingredients with nutraceutical properties such as seaweeds can be utilised to address this challenge. Seaweeds have been used in the food, animal, and pharmaceutical industries as a rich source of nutrients and bioactive compounds. Dietary inclusion of seaweeds in chicken diets has the potential to boost growth and enhance product quality. However, their feed value in indigenous chicken diets is largely unknown. This study investigated the effect of graded levels of green seaweed (Ulva spp.) meal (SWM) on apparent nutrient digestibility, feed intake, growth performance, and blood parameters of Boschveld indigenous chickens, a South African chicken breed. The inclusion of seaweeds boosted feed intake and overall body weight gain but had no effect on nutrient digestibility and efficiency of feed utilisation. Blood parameters were also not affected, except for red blood cell indicators. It was concluded that green seaweeds have the potential to be included in diets of Boschveld indigenous chickens. ABSTRACT: Seaweeds possess a wide range of bioactive compounds that can be beneficial in sustainable intensification systems. This study explored the effect of green seaweed (Ulva spp.) meal (SWM) on apparent nutrient digestibility and physiological responses of Boschveld indigenous chickens. Two-hundred and seventy-five hens (202.4 ± 6.65 g live-weight; 4-weeks-old) were reared on five isoenergetic and isoproteic diets formulated by adding SWM at 0 (SW0), 20 (SW20), 25 (SW25), 30 (SW30), and 35 g/kg (SW35). Neutral detergent fibre digestibility quadratically responded (R(2) = 0.244; p = 0.042) to SWM levels. No significant dietary influences were observed on apparent nutrient digestibility values. Repeated measures analysis showed significant diet × week interaction effect on weekly feed intake and growth performance. Dietary inclusion of SWM increased (p < 0.05) feed intake and overall body weight gain but not feed conversion efficiency. No significant linear and quadratic trends were observed for blood parameters except for basophils (R(2) = 0.172; p = 0.047), which linearly declined with SWM levels. Dietary SWM inclusion only influenced (p < 0.05) mean corpuscular volume, mean corpuscular concentration, and mean corpuscular haemoglobin concentration. We concluded that seaweeds have the potential to be used as a feed ingredient for indigenous chickens.