A 6‐week growth trial was conducted to investigate the effect of dietary supplementation with maggot meal (MGM) and soybean meal (SBM) on the growth performance and antioxidant responses of gibel carp (GC) and darkbarbel catfish (DC). The basal diet was formulated to contain 114 g kg−1 fish meal (FM) and 200 g kg−1 SBM. The basal diet was supplemented with either 280 g kg−1 FM (Control), 390 g kg−1 MGM or 450 g kg−1 SBM to obtain three isonitrogenous (crude protein: 380 g kg−1) and isocaloric (gross energy: 16 kJ g−1) diets. For GC, a significant decrease in specific growth rate (SGR) was only observed in fish fed the SBM diet compared with the control (P < 0.05). Principal components analysis (PCA) of GC showed a higher similarity in antioxidant response to dietary supplementation with MGM and SBM proteins between liver and intestine, but the DC did not. The present results suggest that supplementing 390 g kg−1 MGM protein to basal diet cause an enhancement of the antioxidant capacity in GC, but supplementing 390 g kg−1 MGM and 450 g kg−1 SBM proteins to basal diets resulted in a significant attenuation of the antioxidant capacity in DC. 相似文献
Two kinds of culture systems were constructed, namely, an artificial substrate system (novel sponge biocarrier, SB) and a water exchange system (WE), to evaluate the effects of the microalga Haematococcus pluvialis on the water quality and performance of whiteleg shrimp (Litopenaeus vannamei). The results showed that the average NH4+-N concentration with H. pluvialis was lower than those without it. The average concentration of NO2?-N and NO3?-N in SB system were significantly decreased than those present in WE system, but there was no significant difference in SB system. The growth performance of shrimp with H. pluvialis was superior to that without it. The final average weight and growth rate of shrimp in SB1 and WE1 tanks were differed significantly among that present in SB2 and WE2 tanks (p?<?0.05). SB1 tended to have the highest average weight gain and lowest feed conversion ratio. The shrimp survival was significantly higher in SB1 and WE1 tanks (89.06% and 82.29%, respectively) than that present in SB2 and WE2 tanks (78.13% and 48.44%, p?<?0.05). The high-throughput sequencing results showed that the diversity of bacterial communities and the abundance of bacteria related to the nitrogen cycle and the degradation of organic matter were increased. The present study showed that H. pluvialis had positive effects on shrimp culture in using artificial substrate system and water exchange system.
To investigate the differences in gut bacterial community of Parabramis pekinensis at different growth stages, we collected wild P. pekinensis from the Jingjiang region of the Yangtze River, and detected the intestinal microflora structure using high-throughput sequencing technology. Results show that during stage I the dominant bacteria were Proteobacteria, Actinobacteria, and Firmicutes. During stage II, the proportion of Proteobacteria and Actinobacteria decreased, while the proportion of Firmicutes and Fusobacteria increased, especially Clostridium and Cetobacteria increased significantly. During stage III, Cetobacterium had a dominant position, while the proportion of Firmicutes decreased slightly. In stage IV, the male and female fish showed obvious differences. In the female gut, the proportion of Proteobacteria increased to the first place, while Fusobacteria decreased to the second place. In the male fish, the proportion of Fusobacteria dropped to the fifth, especially that of Cetobacterium decreased significantly, and that of Verrucomicrobia increased. In stage V, the proportion of Fusobacteria increased again to the first place, while Proteobacteria did not decrease significantly in the female gut. The gut bacterial community in males changed into a structure similar to stage I. In stage VI, the gut bacterial community in both females and males changed into a structure similar to stage I. There were significant differences in the intestinal microflora structure of P. pekinensis at different gonad development stages and sexes. To some extent, the changes in intestinal microflora structure reflect the changes in the nutritional requirements of P. pekinensis.
This study was conducted to evaluate the effects of dietary thiamin on the physiological status of the juvenile grouper, Epinephelus coioides. Graded levels of thiamin (0.08, 0.50, 2.12, 3.15, 4.63, 12.37 mg thiamin kg−1 diet) were fed to grouper juveniles (mean weight: 16.97 ± 0.14 g) for 10 weeks. Although fish fed the thiamin-deficient (TD)
diet showed no obvious symptoms of thiamin deficiency or increased mortality, those fed the lowest doses of thiamin (0.08
and 0.50 mg thiamin kg−1 diet) had significantly decreased transketolase activity in the liver. In addition, the level of liver thiobarbituric acid
reactive substances in fish fed the TD diet was 33–67% higher than that in fish with the thiamin-supplemented diet. There
were no significant differences in superoxide dismutase activity between the different groups of fish. 相似文献
