Resposta alimentar do camarão Penaeus vannamei frente a diferentes relações dietéticas entre as farinhas de peixe e krill

Abstract

Fish meal is an important protein source in diets for marine shrimp due to its high nutrient bioavailability and its ability to stimulate shrimp feeding activity. However, its use has been declining due to price volatility and availability. This study aimed to evaluate the feeding responses of juvenile Penaeus vannamei to different dietary inclusion levels of fish meal (FM) and krill meal (KM). Twelve diets were formulated with FM inclusion levels of 9.0, 6.0, and 3.0 (% of the diet, as-fed basis) in combination with 1.5, 3.0, 4.5, and 6.0% KM, along with a control diet containing 12.0% FM. Shrimp with an initial body weight of 14.55 ± 0.57 g were stocked in 50 tanks of 0.5 m³ at a density of 40 shrimp per tank or 70 shrimp/m². The feed preference assessment involved simultaneously offering two distinct diets in each tank, provided ad libitum twice daily. Diets were exclusively presented in two round feeding trays placed at the bottom of the tank, positioned opposite each other. The apparent feed consumption (AFC, %) was determined by dividing the amount of unconsumed dry feed (g) recovered from the feeding trays after 1 h of water exposure by the amount of dry feed delivered (g), multiplied by 100. A total of 7,000 feeding observations were recorded over seven consecutive weeks. Diets 12-0, 9-1.5, 9-3, and 6-1.5 (FM-KM, %) showed the highest AFC values. The AFC results for diets 9-1.5, 9-3, and 6-1.5 were not statistically different. Diets containing 1.5% KM exhibited higher AFC values compared to diets with 3.0, 4.5, and 6.0% KM within their respective FM groups. Among the best-performing diets, diet 6-1.5 stood out with high AFC values, enabling a 50% reduction in FM inclusion when combined with lower KM levels. This highlights a positive interaction between these two protein ingredients when their inclusion levels are adjusted, suggesting the feasibility of reducing marine protein use for sustainability reasons while also promoting better economic balance in whiteleg juvenile shrimp diets.