Concentrado proteico de semente de abóbora (Cucurbita moschata) na nutrição do jundiá

Abstract

This study aimed to evaluate the effects of adding protein sources coming from the pumpkin seed in growth, activity of proteolytic digestive enzymes and metabolic responses of silver catfish (Rhamdia quelen) fed with increasing replacement of fishmeal by pumpkin seed meal (PSM) or phosphorylated protein concentrate of pumpkin seed (PPCPS). For the development of protein concentrate, the method was optimized by statistical methodology of response surface (MRS) and central composite rotational design (CCRD). The CCRD pointed as the highest yield 50.04%, using 4% sodium trimetaphosphate (STMP) at pH 4.5. Those same experimental conditions the protein content was 62.56%. Subsequently, the PSM and PPCPS were used as substitutes in silver catfish protein diets. For eight experimental weeks, 400 silver catfish, with a body mass of 24 ± 0.46 g were divided into 24 fiber glass, fed five experimental diets in four replicates. For the data, four orthogonal contrasts were applied: Control Diet vs. PSM Diets, Control Diet vs. PPCPS Diets, Control Diet vs. Other Diets and PSM Diets vs. PPCPS Diets. Treatment groups replaced 25 to 50 percent protein fishmeal by PSM and PPCPS. Silver catfishes were evaluated for growth parameters, digestive indices, activities of digestive enzymes trypsin and chymotrypsin, as well as metabolic parameters in plasma and liver. The fish growth parameters showed a significant difference (P <0.05) for final body weight at the end of the trial period in contrast Control Diet vs. PSM Diets. Feed conversion was higher for fish that received 25% or 50% PPCPS than those that received PSM (P <0.05). The fish receiving the Control Diet had the lowest digestive-somatic index in contrasts Control Diet vs. PPCPS Diets and Control Diets vs. Other Diets. The control fish treatments showed lower activity of trypsin and chymotrypsin enzymes than fish fed the PSM diet (P <0.05). Also, less chymotrypsin activity was observed in the fish that received the PSM diet (P <0.05), in contrast PSM Diets vs. PPCPS Diets. The fish that received the PPCPS Diets had higher protein efficiency rate than fish fed the FSA (P <0.01). For albumin in plasma, low contents were found in fish that received Control Diet (P <0.05). The ALAT activity was high in fish that received Control Diet (P <0.05), in contrasts Control Diet vs. PSM Diets, Control Diet vs. PPCPs Diets and Control Diet vs. Other Diets. The ALP was most active in fish that received the PPCPS diets (P <0.05), in contrasts Control Diet vs. PPCPS Diets and Control Diet vs. Other Diets. Thus, it can be concluded that the replacement of fishmeal protein by 25 or 50% PPCPS not alter growth and improve the feed conversion catfish and protein efficiency ratio, without affecting the activity of digestive enzymes, metabolic parameters intermediate and liver of silver catfish, can be used in silver catfish nutrition.