Browsing by Author "Zhenyu, Du"

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    Effects of dietary protein to energy ratio on growth, body composition and digestive enzyme activities in Eriocheir sinensis.
    (Wiley, 2016-04-16) Yanyan, Cui; Qianqian, Ma; Samwel Mchele Limbu; Zhenyu, Du; Nannan, Zhang; Erchao, Li; Liqiao, Chen
    This study aimed to determine the optimal protein to energy ratio (P/E ratio) and evaluate the effect of dietary protein and lipid levels on growth performance, body composition and digestive enzymes activities in Chinese mitten‐handed crab, Eriocheir sinensis. Nine practical diets containing three levels both for protein (DP 30%, 35% and 40%) and lipid (DL 2%, 7% and 12%) with P/E ratios ranging from 13.69 to 19.79 mg KJ−1 were fed to four replicates of crabs (3.39 ± 0.10 g) for 10 weeks. Weight gain increased significantly with the increase in DP level at each DL level. Moreover, weight gain increased in crabs fed with diets containing DL level from 2% to 12% and DP level from 30% to 35%. However, the diet containing 40% DP and 12% DL levels significantly decreased the growth performance and protein efficiency of the crabs. The whole crab and hepatopancreas lipid contents also increased as dietary lipid increased, but not dietary protein. The total protease activity increased significantly with the increase in dietary protein at each lipid level. The lipase activity was statistically comparable among different DL levels at each DP level. Taken together, the crab fed the diet containing 35% protein and 12% lipid levels with P/E 15.77 mg KJ−1 revealed optimal growth, feed utilization efficiency and digestive enzymes activities. Moreover, our study indicated that the higher dietary lipid level at a relatively lower dietary protein level could provide protein sparing effect in Eriocheir sinensis.
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    The Physiological and Metabolic Differences between Visceral and Subcutaneous Adipose Tissues in Nile tilapia (Oreochromis niloticus).
    (The American Physiological Society, 2017-11-09) Ya-Wen, Wang; Ji-Lei, Zhang; Jian-Gang, Jiao; Xiao-Xia, Du; Samwel Mchele Limbu; Fang, Qiao; Mei-Ling, Zhang; Dong-Liang, Li; Zhenyu, Du
    Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SCAT) have different structures and metabolic functions and play different roles in the regulation of the mammal endocrine system. However, little is known about morphology and physiological and metabolic functions between VAT and SCAT in fish. We compared the morphological, physiological, and biochemical characteristics of VAT and SCAT in Nile tilapia and measured their functions in energy intake flux, lipolytic ability, and gene expression patterns. SCAT contained more large adipocytes and nonadipocytes than VAT in Nile tilapia. VAT had higher lipid content and was the primary site for lipid deposition. Conversely, SCAT had higher hormone-induced lipolytic activity. Furthermore, SCAT had a higher percentage of monounsaturated and lower polyunsaturated fatty acids than VAT. SCAT had higher mitochondrial DNA, gene expression for fatty acid β-oxidation, adipogenesis, and brown adipose tissue characteristics, but it also had a lower gene expression for inflammation and adipocyte differentiation than VAT. SCAT and VAT have different morphological structures, as well as physiological and metabolic functions in fish. VAT is the preferable lipid deposition tissue, whereas SCAT exhibits higher lipid catabolic activity than VAT. The physiological functions of SCAT in fish are commonly overlooked. The present study indicates that SCAT has specific metabolic characteristics that differ from VAT. The differences between VAT and SCAT should be considered in future metabolism studies using fish as models, either in biomedical or aquaculture studies.
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    Soybean and cottonseed meals are good candidates for fish meal replacement in the diet for juvenile Macrobrachium nipponense. , 26(1): 309–324.
    (Springer, 2017-11-13) Yujuan, Huang; Nannan, Zhang; Wujiang, Fan; Yanyan, Cui; Samwel Mchele Limbu; Yunlong, Zhao; Fang, Qiao; Liqiao, Chen; Zhenyu, Du; Dong-Liang, Li
    Macrobrachium nipponense is a new aquaculture species with high market demand and is preferred as food by Asian consumers. However, its nutrient requirements and optimal dietary sources have not been fully evaluated. In the present study, we examined four common plant protein sources (soybean meal, cottonseed meal, rapeseed meal, and peanut meal) as partial replacement for 25% fishmeal protein in five isonitrogenous and isocaloric diets in M. nipponense for 8 weeks. The nutritional effects of the four plant protein sources were compared by means of growth performance, feed efficiency, histology, biochemical composition, oxidative stress, total hemocyte count, and in vitro digestion. Prawns fed the diets containing soybean (730.96 ± 33.50%) and cottonseed meals (672.32 ± 74.52%) had higher weight gain than those fed on rapeseed (503.71 ± 50.85%) and peanut (507.79 ± 52.10%) meal diets (p < 0.05). Similarly, the feed conversion ratios of prawns fed on soybean (1.66 ± 0.12%) and cottonseed (1.88 ± 0.06%) meal diets were significantly lower than those fed on rapeseed (2.37 ± 0.10%) and peanut (2.77 ± 0.16%) (p < 0.05) meal diets. No significant differences were found among groups in the hepatopancreas and intestinal histological characteristics, activities of antioxidant enzymes, and hemocyte number. The amino acid composition in diets and prawn muscles was comparable among groups. Soybean meal showed the highest in vitro digestibility. Taken together, soybean and cottonseed meals could be good candidates for partial fishmeal replacement in M. nipponense diets.