Effect of dietary protein levels on the growth, enzyme activity, and immunological status of Culter mongolicus fingerlings

Abstract

A 65-day growth trial was conducted to investigate the dietary protein requirements for Culter mongolicus fingerlings. Isolipidic and isoenergetic diets were formulated with five dietary protein levels (32%, 37%, 42%, 47%, and 52%). Each diet was assigned to triplicate groups of 70 C. mongolicus fingerlings (0.99±0.08 g). The results indicated that weight gain and specific growth rate (SGR) increased with increasing dietary protein levels up to 47%. The activities of intestinal trypsin and lipase were the lowest in the 32% protein and 52% protein groups, while amylase activity reduced markedly in the 47% protein group. These results suggest that different dietary protein levels may cause different transformations of nutrients. The activities of superoxide dismutase (SOD) and lysozyme were not affected by varying dietary protein levels, except for those in the 32% protein group. In contrast, the content of malondialdehyde (MDA) increased with increasing dietary protein levels and reaching a maximum in the 52% protein group, suggesting that MDA accumulation depends on the protein concentration and the potential oxidative stress. Taken together, based on the broken-line analysis of SGR, we recommended the optimum dietary protein for C. mongolicus fingerlings to be 48.97%~49.31%.

Efficacy of an Insect-Based Diet with Addition of Probiotics on Growth, Proximate Composition, Enzymatic Efficiency, and Immune Response of Nile Tilapia

“…In T 1 and T 5 , the highest protease enzyme activity resulted in the highest weight gain because studies have shown that protease enzymes directly influence the growth parameters, including weight, FCR, and SGR [61,62]. 12 Aquaculture Nutrition Protease catalyzes the larger protein molecules into smaller subunits, i.e., amino acids, which ultimately help to utilize the available feed [63]. In the T 2 and T 6 groups, both protease enzyme activity and weight gain were also significant compared to the control group, indicating the excellent health profile in fish.…”

Effects of Different Feeding Regimes on Growth Performance, Survival Rate, Carcass Composition, Fatty Acids Profile, and Digestive Enzyme Activities of Great Sturgeon (Huso huso Linnaeus, 1758) Larvae

“…It has been reported that the change of lipase enzyme activity (Figure 4) follows the same pattern as trypsin enzyme activity. Excessive amounts of protein may turn into massive fat deposits, and thus inhibit the lipase activity [18]. The lipase activity in FR-A followed by FR, D, and E was significantly more than others FR (e.g., in FR-A was 61.18% higher than FR-F; p<0:05).…”

“…In this time, trypsin activity in FR-A followed by FR-E was significantly more than others FR (p<0:05). In this connection, it has been reported that the lack of amino acids that are responsible for the synthesis and secretion of trypsin can lead to the lack of proper activity of the trypsin enzyme [18]. At 38 dph, pepsin activity in FR-A followed by FR-D and E was significantly more than other FR (p<0:05).…”

“…In this connection, it has been reported that the amount of dietary protein has an effect on protease activity, but protease activity is different among species. It has been found that there is no correlation between protease activity and protein level diets in some fish species (Labeo rohita fingerlings, Dentex dentex, Cyprinus carpio, Anarhichas minor, and Cherax quadricarinatus) [18]. Among the different enzymes, the activity of pancreatic enzymes activity (e.g., amylase, trypsin, and lipase) is usually used as an indicator of the activity and readiness of the digestive system [44].…”

“…Digestive enzymes are important in term of nutrient digestion. The activity level of digestive enzymes is a useful indicator of food utilization, digestibility, and growth performance of fish [18]. The purpose of the study was to determine the impact of feeding with LF and microdiet on growth performance, survival rate, carcass composition, fatty acids profile, and digestive enzyme activities in other to introduce the best FR in great sturgeon larvae.…”