Hidrolisado enzimático de penas de frango em dietas para tilápia do Nilo (Oreochromis niloticus): desempenho produtivo e atratopalatabilidade

Abstract

The use of agro-industrial by-products such as viscera, blood, skins, and feathers can be an excellent alternative to fishmeal in aquaculture. This study evaluated the effects of including enzymatically hydrolyzed chicken feathers (HEP), supplied by BRF Ingredients®, in diets for juvenile Nile tilapia (Oreochromis niloticus). The experiments were conducted at the Aquaculture Laboratory of the Aquaculture Management Study Group – GEMAq, at the Western Paraná State University (UNIOESTE), Toledo Campus, Brazil, over a 50-day period for zootechnical performance and 23 days for the attractability and palatability trial.Three isoproteic diets were formulated with 0% (control diet), 1%, and 2% HEP. For productive performance, a completely randomized design was used, with 24 polyethylene tanks and 15 juveniles averaging 9.0 ± 1.0 grams, totaling 360 fish. Feeding occurred four times a day (8 a.m., 11 a.m., 2 p.m., and 5 p.m.). Tank cleaning was performed twice daily, with a partial water exchange of 30%. Dissolved oxygen averaged 4.9 ± 0.5 mg L⁻¹; pH was 7.2 ± 0.01, measured weekly, and temperature was 28.7 ± 0.3°C, measured daily using a multiparameter probe (YSI® Professional Series). Ammonia levels were 0.29 ± 0.05 ppm; nitrite 0.4 ± 0.001 ppm; and soft water hardness were monitored every three days using a LabconTest® colorimetric kit.After the experimental period, zootechnical parameters such as weight gain, specific growth rate (SGR), apparent feed conversion ratio (FCR), hepatosomatic index (HSI), viscerosomatic index (VSI), and carcass proximate composition were analyzed. For the attractability and palatability study, 12 Nile tilapia fingerlings (O. niloticus) with an initial average weight of 7.54 ± 0.39 g and standard and total lengths of 6.18 ± 0.16 cm and 7.73 ± 0.20 cm, respectively, were used. The fish were fed six times a day (8 a.m., 10 a.m., 12 p.m., 2 p.m., 4 p.m., and 6 p.m.). To obtain results, a GoPro® 5 Black 4K Ultra HD camera was used for recording, and attractability-palatability indices (API) were measured based on behavioral parameters such as time to capture the first pellet, number of pellets consumed, rejections, and approaches.Results suggest that the diet containing 2% enzymatically hydrolyzed chicken feathers (HEP) promoted better performance in terms of weight gain and SGR, without negatively affecting physiological indices or carcass composition. Regarding attractability and palatability, positive behavioral responses were observed at specific feeding times, especially for diets containing 1% and 2% HEP, resulting in higher consumption and lower feed rejection. The inclusion of up to 2% HEP proved to be a viable alternative protein source for the formulation of efficient and sustainable diets for tilapia, contributing to the utilization of these agro-industrial by-products in aquaculture.