J.M. Su

Bio: J.M. Su is an academic researcher from Huazhong Agricultural University. The author has contributed to research in topics: Phytase & Genome. The author has an hindex of 1, co-authored 1 publications receiving 31 citations.

Apparent digestibility of nutrients in grass carp (Ctenopharyngodon idellus) diet supplemented with graded levels of neutral phytase using pretreatment and spraying methods

Abstract: The effects of supplemental graded levels of neutral phytase using pretreatment and spraying methods on the apparent digestibility coefficients (ADCs) of protein, minerals and amino acids were investigated in grass carp (Ctenopharyngodon idellus) (mean weight, 20.92 ± 1.04 g). Seven experimental diets were prepared as: no-phytase supplementation (control), pretreatment with phytase dose of 500 U (PP500), 1000 U (PP1000) and 1500 U (PP1500) per kg diet. With spraying method, the phytase was added to feed at the same three grades, namely 500 U (PS500), 1000 U (PS1000) and 1500 U (PS1500) per kg diet. After an 8-week feeding trial, addition of phytase improved the crude protein, crude lipid, dry matter, ash, phosphorus and calcium digestibilities in comparison with the control, especially in the diets where phytase addition level was above 1000 U kg−1 (P < 0.05). Phytase supplementation, both the pretreatment and spraying, significantly enhanced the ADCs of essential amino acid (EAA) and non-essential amino acid. The ADCs of the nutrients were significantly influenced by phytase supplementation methods, supplementation levels and interaction of methods and levels. Based on the results, supplemental dietary phytase, regardless of application methodology, improved the ADCs of nutrients in grass carp, and the pretreatment mode of phytase application was more effective than spraying at the same phytase level. We suggest that the optimal level of phytase pretreatment is 1000 U kg−1 diet, and the best addition level of phytase spraying is 1500 U kg−1 diet or more phytase is required for spraying.

Isolation and Phylogenetic Analysis of a Hunnivirus Strain in Water Buffaloes From China

Abstract: In recent years, hunniviruses have been reported in a variety of animal species from many countries. Here, hunnivirus was detected in fecal samples from water buffaloes and named as BufHuV-GX-2106. The samples were inoculated into cultures of MDBK cells supplemented with TPCK trypsin and the BufHuV-GX-2106 strain was stably passaged and replicated. Electron microscopic analysis showed the BufHuV-GX-2106 virus particles were spherical and 20~30 nm in diameter. The complete genome of a plaque purified sample of BufHuV-GX-2106 was determined and analyzed. Genomic analysis revealed that the whole sequence of BufHuV-GX-2106 was ~7,601 nucleotides (nt) in length and consisted of a large open reading frame of 6,759nt, a 5′UTR, a 3'UTR and a poly(A) tail. The complete genome sequence of BufHuV-GX-2106 shares 68-85% nucleotide identities with other known hunnivirus strains, indicating high genetic heterogeneity among these viruses. Phylogenetic analysis showed that BufHuV-GX-2106 belonged to the Hunnivirus A species and was more closely related to ovine hunnivirus than other known viruses of this type. This study describes the first isolation and complete genome sequence of a hunnivirus strain from water buffaloes. In addition, this study will help to understand the mechanisms involved in the pathogenesis of Hunnivirus A among different animal species.

A review of the effects of ingredient composition and processing conditions on the physical qualities of extruded high‐energy fish feed as measured by prevailing methods

Abstract: Feed comprises the biggest cost in intensive fish farming and the quality of feed is therefore important. A vast body of research has been carried out in order to investigate nutritional quality of alternative ingredients. Effects of ingredients on physical quality are seldom included in these investigations. Physical quality of feed varies with ingredient composition and processing condition and may interfere with feed intake, nutrient digestibility and therefore growth performance of the fish. In this review, physical quality of extruded, high energy feed, and how ingredient composition and processing conditions affect the quality will be addressed. Various pellet properties will be discussed and methods used to evaluate physical quality will be reviewed.

Use of phytases in fish and shrimp feeds: a review

Abstract: Phytases have been employed in animal feeds for several years, used primarily for reducing the environmental impact and phosphorus loads of farm effluents. Beneficial effect of dietary phytase has been associated with the limited ability of monogastric animals to utilize dietary plant phytates. To date, numerous studies have shown the positive effect of phytase supplementation on the availability of dietary phosphorus and trace minerals within plant-based feeds for monogastric farm animals, including farmed fish and shrimp. Individual feed ingredients may also be improved with phytases as an exogenous treatment, also termed pre-conditioning dephytinization prior to mixing. This review presents data on the potential benefit of phytase application for fish and shrimp species in improving digestibility of phosphorus and other minerals as well as organics nutrient fractions such as protein, amino acids and lipids.

Effects of temperature and feed processing on protease activity and dietary protease on growths of white shrimp, Litopenaeus vannamei, and tilapia, Oreochromis niloticus × O. aureus.

Abstract: Effects of temperature and processing on the stability of a commercial protease were assessed in an in vitro trial followed by growth trials with white shrimp and tilapia. Results showed that the protease has a high heat stability against pelleting, and it could hydrolyse dietary proteins during feed processing. In Exp. 2, white shrimp (3.3 g) fed low fish meal (FM) diet (LFD) with protease addition had similar growth to that fed high fish meal diet, and both had higher weight gain (WG) and lower feed conversion ratio (FCR) than that fed LFD without protease addition (P < 0.05). In Exp. 3, compressed (CD) or extruded (ED) diets containing 30 g kg−1 or 90 g kg−1 FM were supplemented with or without protease and then fed to tilapia (1.7 g) for 8 weeks. WG was improved and FCR decreased (P < 0.05) by the supplementation of protease in 30 g kg−1 FMCD, but not in 90 g kg−1 FMCD and ED diets when compared to those diets without protease supplementation. The digestibility trial with CD indicated the improved apparent digestibilities of dry matter and crude protein by dietary protease in 30 g kg−1 FMCD, but not in 90 g kg−1 FMCD. Results above showed that the protease has a high heat stability and the supplementation of protease in CD with low FM level can improve the growth of shrimp and tilapia.