The effect of water temperature on food transit time and digestive enzymes activity in Caspian kutum (Rutilus kutum) larvae

The present study investigates the effects of water temperature on digestive enzymes activity and food transit time in Caspian kutum (Rutilus kutum) larvae. Caspian kutum larvae (532 ± 0.05 and 543 ± 0.02 mg) were divided into two groups with three replicates and reared at different water temperature i.e. 25.6 ± 0.4°C (T1) and 18.4 ± 0.1°C (T2). At the end of the experiment, sampling of intestine was performed at 0, 1, 3, 5, 8, 16, 24 and 30 h after feeding from each treatment. In T2, food was observed until 24 h after feeding and the intestine was empty 29 h after feeding, while in T1 19 h after feeding the intestine was empty. Digestive enzymes activities were higher in T2 treatment. The peaks of trypsin and alkaline phosphatase enzymes activity were found 8 h after feeding in T1, while occurred 16 h after feeding in T2. The highest chymotrypsin and alpha-amylase enzymes activity were observed 5 and 8h after feeding in T1 and T2, respectively. These results confirmed remarkable effects of temperature on food transit time and digestive enzymes activity of Caspian kutum

Hemato-immunological, serum metabolite and enzymatic stress response alterations in exposed rainbow trout (Oncorhynchus mykiss) to nanosilver

The aim of present study was to investigate the effects of sub-lethal concentrations of silver nanoparticles (AgNP) on hematological parameters, differential tests of white blood cells, serum metabolite parameters, serum enzymes activity and serum ions in rainbow trout, Oncorhynchus mykiss. Healthy rainbow trout, were exposed to sub-lethal concentrations (0, 1.5 and 2.5 ppm) of nanosilver for 14 days. RBC, WBC and Hct levels were significantly (P<0.05) increased in exposed groups. Within the white blood cells, only neutrophils showed a significant increase at 7 and 14 days post exposure (P<0.05). Serum triglyceride, total serum protein, albumin and globulin levels were decreased (P<0.05) in exposed fish, however, cholesterol levels increased in the 2.5 ppm group at 7 days after exposure (P<0.05). Cortisol and glucose increased significantly at 7 and 14 days of exposure in both concentrations of AgNPs (P<0.05). Decreases in serum ions level were observed, although reduction in chloride ions occurred earlier and more severe than other measured parameters (P<0.05). Elevation in serum ALP, LDH, ALT and AST enzymes were observed during the experiment (P<0.05), although SOD and CAT activity were significantly decreased in exposed groups (P<0.05). The results revealed that AgNP can affect the hematological, serum metabolite and enzymatic parameters of O. mykiss, as well as AgNP exposure induce a general oxidative stress response in O. mykiss