Effect of garlic (Allium sativum) extract on growth, enzymological and biochemical responses and immune-related gene expressions in giant freshwater prawn (Macrobrachium rosenbergii).

In the current study, growth performance, biochemical constituents of muscle, activities of enzymes in the haemolymph, and expressions of immune-related genes were evaluated in the giant freshwater prawns Macrobrachium rosenbergii fed diets supplemented with aqueous garlic (Allium sativum) extract at 0, 5, 10 and 20 g/kg (w/w) for 60 days. At the end of the feeding trial, weight gain and specific growth rate were significantly improved in garlic-fed prawn groups compared with the control (p < 0.05). Moreover, feed conversion ratio was significantly lower in the garlic-fed groups than in the control (p < 0.05). Activities of catalase, superoxide dismutase and glutathione peroxidase in the hepatopancreas, activities of alanine aminotransferase, aspartate aminotransferase and levels of albumin and total protein in the hemolymph were significantly increased in the garlic treatments (p < 0.05). Furthermore, garlic supplemented diets improved muscle biochemical profiles, particularly contents of crude protein and total ash and upregulations of immune deficiency and heat shock proteins (HSP70) gene expression (p < 0.05). Therefore, garlic has positive effects on growth performance and physio-biochemical responses of M. rosenbergii, and thus, it can be used as an additive for stress resistance and as a growth promoter in sustainable aquaculture.

Selenium nanoparticle and selenomethionine as feed additives: effects on growth performance, hepatic enzymes' activity, mucosal immune parameters, liver histology, and appetite-related gene transcript in goldfish (Carassius auratus).

The aim of this study was to assess the effects of different dietary selenium sources, selenium nanoparticle (nSe), and selenomethionine (SeMet) as feed additives on growth performance, hepatic enzymes' activity, biochemical, mucosal immune parameters, liver histology, and appetite-related gene transcript in goldfish (Carassius auratus). At first, goldfish juveniles (n=480; mean 4.54 g) were fed dietary selenium nanoparticle at 0, 0.3, 0.6, and 0.9 mg nSe/kg diet and SeMet at 0, 0.3, 0.6, and 0.9 mg Se/kg for 9 weeks. Growth performance was evaluated using standard procedures. Blood, skin mucus, and tissue samples (liver and intestine) were collected for biochemical, mucosal immune response, histology, and ghrelin and insulin-like growth factor-I (IGF-I) gene expression. The results showed that fish fed diets fortified with 0.6 mg nSe/kg and 0.6 mg Se/kg had a significant higher weight gain, specific growth rates (SGR), and lower feed conversion ratios (FCR) than fish fed basal diets (p<0.05). Furthermore, dietary nSe and SeMet enhanced blood biochemical profiles especially alkaline phosphatase (ALP) (p < 0.05) and mucosal immunity than the control group in goldfish. Moreover, the liver histological investigation showed that fish fed 0.9 mg of SeMet and nSe kg-1 diets had higher liver lesion scores such as karyolysis, lipidosis, and hyperemia while fish fed 0, 0.3, and 0.6 mg of SeMet and nSe kg-1 diets had small liver changes at 9 weeks. The study further established that inclusion of nSe and SeMet in the diet of goldfish greatly promoted ghrelin and IGF-1genes expressions (p <0.05). Overall, dietary nSe performs better than SeMet and basal diets. The results evoked that nSe and SeMet stimulate the growth, biochemical, and mucosal immunity in goldfish at 0.6 mg/kg.