Effects of single and combined supplementation of Lactobacillus plantarum with dietary xylooligosaccharide on growth performance, body composition and physiological responses of sobaity (Sparidentex hasta) fingerling

The aim of this study was to evaluate the single and combined effects of dietary probiotic with prebiotic on growth performance, non-specific immune response, body composition, digestive enzymes activity and intestine bacterial flora of sobaity fingerling (Sparidentex hasta). For this purpose, 425 individuals of sobaity fingerlings were prepared with an average weight of 7.64 ± 0.3 g from the Mariculture Research Station of South Iranian Aquaculture Research Center. This study was carried out in a completely randomized design with four treatments and three replications (45 fish per each replication) in fiberglass tanks with 300 liters volume. Fish were fed with feed containing 0 (control group), 10^6 CFU probiotic per gram feed (treatment 1), 0.5 and 1 percent prebiotic plus10^6 CFU probiotic per gram feed (treatment 2 and 3) at 4.5 percent of body weight for a period of 42 days. At the end of the experiment, body composition, intestine, blood, plasma and mucus samples were collected. The obtained results indicated that dietary prebiotic and probiotic did not change growth performance, intestine bacterial flora and non-specific immune response of sobaity (P > 0.05). Nonetheless, plasma bactericidal activity of control group was significantly higher that treatment 3 (P < 0.05). Moisture and protein content of treatment 2 showed significant different compared to the control group (P < 0.05). The results of this study showed that digestive enzymes activity including alkaline protease, amylse and lipase affected by administration of dietary prebiotic and probiotic (P < 0.05). Overall, this study showed that single supplementation of probiotic and combination with prebiotic at the used amounts had no positive effects on growth performance and intestine bacterial flora and immune response (except plasma bactericidal activity) of sobaity but improve digestive enzymes activity

Effects of intermittent feeding on compensatory growth, feed intake and body composition in Asian sea bass (Lates calcarifer)

This experiment was conducted to investigate the effects of various starvation and refeeding periods on growth, feed utilization and body composition in Asian sea bass (Lates calcarifer) with an average initial weight of 30.26±1.4 g (mean±SE). The fish were exposed to three different regimes: the control group fed twice daily to apparent satiation throughout the experiment (C), the first group starved for 4 days and refed for 16 days, this cycle was repeated two times (T1) and the second group starved for 8 days and refed for 32 days (T2). At the end of experiment, there were not any significant differences in growth and feeding performance among different treatments (p>0.05). Daily feed intake was significantly higher in the deprived fish than in the control fish (p0.05). Starvation had a significant effect on protein content on one sampling date during the experimental period; protein content in T2 on day 8 was significantly lower compared to the control (p<0.05). Sea bass showed complete compensation indicating a high ability of the deprived fish to grow sufficiently to fully compensate for weight loss during starvation. The results suggested that the feeding schedule involving starvation-refeeding cycles could be a promising feed management option for the culture of this species

Effects of dietary probiotic (Lactobacillus plantarum) on body composition, serum biochemical parameters and liver enzymes of Asian sea bass (Lates calcalifer, Bloch 1790)

In the current study, the effects of different levels of probiotics, Lactobacillus plantarum in the diet of Asian sea bass, Lates calcarifer on body composition, serum biochemical parameters (glucose, cholesterol, triglyceride and albumin) and liver enzymes (lactate dehydrogenase, alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase) were investigated. This experiment was carried out with three treatments and a control group for a period of four weeks. The treatments were included 0, 1×106, 2×106, 3×106 colony forming unit (CFU) gram probiotic in each gram of basic diet. Fish with an average weight of 50.26 ±0.89 grams were randomly distributed in tanks and in each tank stocked 20 pieces of fish. Feeding was done twice a day. The obtained results indicated that the use of different levels of probiotic in diet of Asian sea bass had no significant effects on serum biochemical parameters and liver enzymes. The different levels of probiotic did not affect protein, ash and moisture values between the treatments and the control group (P> 0.05). Moreover, fat value in the fish T2 and T3 was significantly higher (P< 0.05) than the fish control and T1. Also, nitrogen free extract (NFE) value varied significantly (P < 0/05) between the control and the fish T3. Overall, this study indicated that this probiotic had no significant effect on some blood biochemical parameters and liver enzyme, but at the high level can positively influence on body composition of Asian sea bass

Physiological and morphological response to short-term starvation and re-feeding in sub-yearling siberian sturgeon (Acipenser baerii Brandt, 1896): effects of compensatory growth

In this study, the capacity of Siberian sturgeon, Acipenser baerii with mean weight 19.3±0.4 g to face short-term starvation and subsequent re-feeding was assessed for a 40-day period. To investigate, the effect of compensatory growth on some physiological response (plasma cortisol, thyroid hormones, glucose, protein, cholesterol and triglyceride) and morphological (total body weight and length, condition factor, hepato-somatic index, vicero-somatic index and digestive-somatic index) in Siberian sturgeon four different feeding regimes were established. Control group fed four times daily to apparent satiation; SRF1: 2 days starvation and 8 days refeeding; SRF2: 4 days starvation and 16 days refeeding; SRF3: 8 days starvation and 32 days refeeding were experienced. At the end of experiment, blood samples were collected to analyze biochemical parameters. Plasma cortisol and thyroxin (T_4) hormones levels were not significantly different between control and food deprived groups at the end of experiment (P>0.05) but plasma tri-iodothyronin (T_3) levels were lower in the starved groups compared to control animals, but this decreases only in S1 group was significant (P0.05). Moreover, at the measured morphometric indices were not observed significantly different between the control and starved groups (P>0.05). The results suggest that Siberian sturgeon has the physiologic and metabolic adjustment ability to shortterm starvation and return to basal level after re-feeding

Cortisol and its metabolites in juvenile Siberian sturgeon, Acipenser baerii Brandt, 1869 in response to short-term food deprivation

In this study, the effect of short-terms starvation (0, 2, 4 and 8 days) on plasma cortisol, glucose, triglyceride and cholesterol levels and also hepatosomatic index in Siberian sturgeon, Acipenser baerii, was investigated. After acclimation to experimental conditions for 10 days using formulated diet, 180 juvenile Siberian sturgeons (mean weight ± S.E.=19.3±0.4, n=15) were randomly distributed among twelve circular, 500l, fiber glass holding tanks with a flow-through system. In this study, control fish (C) were fed with formulated diet to apparent satiation four times daily throughout the experiment. The other three groups were deprived from feed for 2 (T1), 4 (T2) and 8 (T3) days, respectively. Blood samples were taken at the end of the starvation periods for biochemical analyses. Plasma cortisol, triglyceride and cholesterol levels were not significantly different between control and starved fish at the end of the food deprivation periods, but plasma glucose levels were significantly lower in the starved groups, compared to the control fish. HSI index significantly decreased in all starvation groups, except T1, in comparison to the control. The results suggest that energy reserves mobilization during starvation in Siberian sturgeon may be achieved without the involvement of cortisol. Moreover, in this species there are clear indications of metabolic adjustment ability to short periods of food deprivation

Study of cosolvent-induced α-chymotrypsin fibrillogenesis: Does protein surface hydrophobicity trigger early stages of aggregation reaction?

The misfolding of specific proteins is often associated with their assembly into fibrillar aggregates, commonly termed amyloid fibrils. Despite the many efforts expended to characterize amyloid formation in vitro, there is no deep knowledge about the environment (in which aggregation occurs) as well as mechanism of this type of protein aggregation. Alpha-chymotrypsin was recently driven toward amyloid aggregation by the addition of intermediate concentrations of trifluoroethanol. In the present study, approaches such as turbidimetric, thermodynamic, intrinsic fluorescence and quenching studies as well as chemical modification have been successfully used to elucidate the underlying role of hydrophobic interactions (involved in early stages of amyloid formation) in α-chymotrypsin-based experimental system. © 2009 Springer Science+Business Media, LLC

The effect of short-term starvation on some physiological and morphological parameters in juvenile Siberian sturgeon, Acipenser baerii (Actinopterygii: Acipenseriformes: Acipenseridae)

Background. Fish may experience periods of food deprivation or starvation in nature and under culture conditions. Because of the wild  stock reduction of some sturgeon species, Siberian sturgeon, Acipenser baerii Brandt, 1869, has been used as a biological model of physiological and nutritional studies since the 1980s. There are no published records on the physiological responses of Siberian sturgeon to starvation. Hence, in this study the effect of short-term starvation (0, 2, 4, and 8 days) on plasma thyroid hormones (T3 and T4), total protein levels, and hepato-somatic- (HSI), viscero-somatic- (VSI), and digestive-somatic (DSI) indices in juvenile Siberian sturgeon was investigated. Materials and methods. The experiment was conducted at the International Sturgeon Research Institute of Rasht (Iran) in October 2009, using a semi-natural environment (natural photoperiod and natural water temperature fluctuations). After a period of adaptation (10 days on a formulated diet), 180 juvenile Siberian sturgeon individuals (mean weight ± standard error at start of experiment: 19.32 ± 0.43, n = 15) were randomly distributed among twelve circular, 500-L, fibreglass tanks with a flow-through system. In this trial, control (C) was fed a formulated diet to apparent satiation four times daily throughout the experiment. The other three groups were deprived of feed for 2- (2S), 4- (4S), and 8 (8S) days, respectively. At the end of the starvation periods, blood samples were collected to analyze biochemical and physiological parameters. Results. Plasma T3, T4, and total protein levels did not significantly vary between the fed and the starved fish. In comparison to the starved groups, after 8 days of starvation, plasma total protein in group 8S (3.43 ± 0.20) was markedly higher than in 2S (2.67 ± 0.07) and 4S (2.37 ± 0.12) groups. In the presently reported study, a decrease in the measured morphometric indices was observed with an increase in the length of the starvation period. Conclusion. The results suggest that Siberian sturgeon has metabolic adjustment ability to short periods of starvation due to reduced basal metabolism rate and energy reserves utilization during starvation