Ocean University of China

About: Ocean University of China is a education organization based out in Qingdao, China. It is known for research contribution in the topics: Population & Sea surface temperature. The organization has 27604 authors who have published 27886 publications receiving 440181 citations. The organization is also known as: Zhōngguó Hǎiyáng Dàxué & OUC.

Effects of exogenous enzymes (phytase, non-starch polysaccharide enzyme) in diets on growth, feed utilization, nitrogen and phosphorus excretion of Japanese seabass, Lateolabrax japonicus.

Abstract: A feeding experiment was conducted to investigate the effects of exogenous enzymes (phytase, non-starch polysaccharide enzymes: WX and VP, supplied by DSM) on growth performance and excretion of Japanese seabass (Lateolabrax japonicus) (initial mass 6.26 ± 0.10 g). A basal diet was used as a control that contained a mixed protein source, and lysine, methionine and valine were supplemented to simulate the essential amino acid pattern of fish meal. Four other diets were supplemented with 200 mg phytase (500 IU), 400 mg VP, 800 mg WX, or a combination of 800 mg WX and 400 mg VP per kg diet, respectively. Each diet was assigned to triplicate groups of fish in floating sea cages, and each cage was stocked with 60 fish. The results showed specific growth rate (SGR) and feed efficiency ratio (FER) were not significantly improved by the phytase supplementation. However, supplementations with WX and VP significantly enhanced the SGR and FER (P < 0.05). Phosphorus retention was significantly increased by the supplementation with phytase, whereas nitrogen retention was also enhanced by supplementations of non-starch polysaccharide enzymes (P < 0.05). The excretion experiment showed that the soluble phosphorus and ammonia nitrogen in starved fish were constant, irrespective of dietary treatments. The total phosphorus effluent in fish fed the diet with phytase supplementation was significantly lower compared with the control group after feeding to satiation (P < 0.05), but soluble phosphorus excretion was still independent of dietary treatments. The ammonia excretion in satiated fish significantly decreased with supplementations of non-starch polysaccharide enzymes.

Zebrafish IGF genes: gene duplication, conservation and divergence, and novel roles in midline and notochord development.

Abstract: Insulin-like growth factors (IGFs) are key regulators of development, growth, and longevity. In most vertebrate species including humans, there is one IGF-1 gene and one IGF-2 gene. Here we report the identification and functional characterization of 4 distinct IGF genes (termed as igf-1a, -1b, -2a, and -2b) in zebrafish. These genes encode 4 structurally distinct and functional IGF peptides. IGF-1a and IGF-2a mRNAs were detected in multiple tissues in adult fish. IGF-1b mRNA was detected only in the gonad and IGF-2b mRNA only in the liver. Functional analysis showed that all 4 IGFs caused similar developmental defects but with different potencies. Many of these embryos had fully or partially duplicated notochords, suggesting that an excess of IGF signaling causes defects in the midline formation and an expansion of the notochord. IGF-2a, the most potent IGF, was analyzed in depth. IGF-2a expression caused defects in the midline formation and expansion of the notochord but it did not alter the anterior neural patterning. These results not only provide new insights into the functional conservation and divergence of the multiple igf genes but also reveal a novel role of IGF signaling in midline formation and notochord development in a vertebrate model.

Anammox, denitrification and dissimilatory nitrate reduction to ammonium in the East China Sea sediment

Abstract: Benthic nitrogen transformation pathways were investigated in the sediment of the East China Sea (ECS) in June of 2010 using the 15 N isotope pairing technique. Slurry incubations indicated that denitrification, anammox and dissimilatory nitrate reduction to ammonium (DNRA) as well as intracellular nitrate release occurred in the ECS sediments. These four processes did not exist independently, nitrate release therefore diluted the 15 N labeling fraction of NO 3 − , and a part of the 15 NH 4 + derived from DNRA also formed 30 N 2 via anammox. Therefore, current methods of rate calculations led to over and underestimations of anammox and denitrification respectively. Following the procedure outlined in Thamdrup and Dalsgaard (2002), denitrification rates were slightly underestimated by an average 6% without regard to the effect of nitrate release, while this underestimation could be counteracted by the presence of DNRA. On the contrary, anammox rates calculated from 15 NO 3 − experiment were significantly overestimated by 42% without considering nitrate release. In our study, this overestimation could only be compensated 14% by taking DNRA into consideration. In a parallel experiment amended with 15 NH 4 + + 14 NO 3 − , anammox rates were not significantly influenced by DNRA due to the high background of 15 NH 4 + addition. The significant correlation between potential denitrification rate and sediment organic matter content ( r = 0.68, p 2 was the main pathway, while DNRA was also an important pathway accounting for 20–31% of benthic nitrate reduction in the ECS. Our study demonstrates the complicated interactions among different benthic nitrogen transformations and the importance of considering denitrification, DNRA, anammox and nitrate release together when designing and interpreting future studies.