Effect of dietary date seed meal as an alternative carbohydrate source on immune-related gene expression of Pacific white shrimp Penaeus vannamei.

Current study aimed to examine the effect of dietary date seed meal (DSM) as an alternative carbohydrate ingredient on immune-related genes expression of Pacific white shrimp (Penaeus vannamei). A total number of 750 shrimp (4.0 ±â€¯0.1 g) were randomly assigned into five experimental treatments, each with three replicates. Experimental diets contained 0, 50, 100, 150 and 230 g/kg DSM substituted for both wheat and rice flour. Shrimp were fed at a rate of 5% body weight three times daily and the mRNA expression of α2-macroglobulin (α2-M), lipopolysaccharide and beta-1,3-glucan-binding protein (LGBP), integrin ß, and peroxinectin (PX) was studied on five shrimp per treatment after 8 weeks feeding trial. The results showed that replacement of DSM up to 100 g/kg in the diet of P. vannamei caused no significant changes in the expression of α2-M and integrin ß, however both of these genes showed lower expression in shrimp fed diets containing 150 and 230 g/kg DSM compared to control group. Moreover, no significant differences were observed in the expression of PX and LGBP between shrimp fed diets containing different amounts of DSM and control group. These findings demonstrated that as an inexpensive source of carbohydrate, DSM could be substituted up to 100 g/kg for wheat and rice flour in the diet of farmed shrimp without suppressive effects on the immune status.

Evaluation of some qualitative variations in frozen fillets of beluga (Huso huso) fed by different carbohydrate to lipid ratios.

In this study, juvenile beluga (Huso huso) was fed by the diets containing different carbohydrate to lipid ratios for 5 months. At the end of culture period, proximate compositions of the fish carcasses (moisture, protein, lipid, and ash) were measured. Then, qualitative changes in the fishes were evaluated during 6 months frozen storage (-20 °C) along with recording changes in their Total Volatile Bases Nitrogen (TVN), Thiobarbituric Acid (TBA), Free Fatty Acids (FFA), pH, and muscle texture profile analysis. The results of proximate analysis of the carcasses showed that moisture, protein, and ash of the carcasses increased significantly (p < 0.05) with higher carbohydrate to lipid ratio, but lipid content of the carcasses decreased significantly (p < 0.05). Also, during frozen storage, TVN, TBA, and FFA increased significantly in all the samples (p < 0.05). Significant differences were detected in pH of the treatments (p < 0.05), but these changes didn't follow a regular pattern in all the treatments. The results of muscle texture profile analysis showed lower chewiness, hardness, and gumminess during the first 3 months of frozen storage; however, after 6 month, the values increased significantly compared to those in 3 months. Different characteristics of texture showed significant differences in the treatments during frozen storage (p < 0.05), although these changes didn't follow an identical pattern in all the treatments. It can be concluded that carbohydrate higher than 27% in diet has had adverse effect on quality of fillets during frozen storage. However, lipid levels used in the present study haven't had significant influence on quality of the fillets during the preservation.