Dietary Protease improves Production Performance of commercially farmed Pacific White Shrimp Litopenaeus vannamei
Use of dietary protease in aquaculture has been gaining increasing attention. Recently, several studies have shown to improve performance and immune response in Pacific white shrimp when a dietary protease is added. These studies were mostly conducted in Asia where culture conditions, feeds and feeding management are starkly different than those in Americas. Therefore, there is a serious need to evaluate the effects in Latin American conditions, more specifically, under commercial farming conditions. To address this, two trials were conducted in Ecuador. The first trial was conducted for 89 days with four diets, in 12 earthen ponds (400-m2) stocked with 4,000 PL in each pond (Table 1). The second trial was conducted for 90 days in four 2-ha earthen ponds, where each pond was stocked at a density of 10 PL-m-2. Two ponds were fed with a commercial feed with 35% of crude protein. The other two ponds were fed with 28% crude protein diet supplemented with Jefo protease at 175 g MT-1.
In the trial 1, despite no differences in survival (52%-71%), final biomass (kg ha-1), FCR, and SGR among the treatments, weight gain was significantly higher in shrimps fed high marine protein diets with protease (diet 2, 10.0 g ±1.2) than those fed the same diets without the protease (6.4 g ±0.4). As expected, a significantly higher protein efficiency ratio (PER) was observed in shrimps fed the low protein diet with protease (diet 4, 2.4 ±0.2) than those fed diets 1, 2 or 3 (1.7 ±0.1, 1.9 ±0.1 and 1.9 ±0.2, respectively).
In the trial 2, despite no difference in growth (Figure 1), there were large differences in size distribution at harvest between the treatments (P<0.05) that significantly impacted the financial outcomes. It showed importance of dietary protease in commercial farming conditions to bring significant cost savings and profit to the farmers even in low-density farming as practiced in Americas. Our findings show that either decreasing the digestible protein or the crude protein level in the diet can bring significant cost savings for both feed manufacturers and farmers when supplemented with Jefo protease.