Effects of Dietary Protein and Lipid Levels with Different Protein‐to‐Energy Ratios on Growth,Feed Utilization,and Plasma Biochemical Parameters of Dianchi Golden‐line Barbell,Sinocyclocheilus grahami

An 8‐wk feeding trial was conducted to evaluate the effects of varying dietary protein and lipid levels with different protein‐to‐energy (P/E) ratios on growth, feed utilization, and plasma biochemical parameters of Sinocyclocheilus graham. Nine experimental diets were formulated to contain three protein levels (35, 40, and 45%), and each with three lipid levels (4, 8, and 12%), to produce a range of P/E ratios from 71.31 to 98.64 mg protein/kcal. Each diet was randomly assigned to triplicate groups of 25 fish. Fish grew best when fed the diet containing 45% protein and 12% lipid. However, fish fed the diet with 40% protein and 8% lipid had similar weight gain and specific growth rate as those fed the above diet but showed relatively better feed conversion ratio, protein efficiency ratio, and protein and energy retentions. Additionally, plasma total amino acids and blood urea nitrogen contents and γ‐glutamyltransferase, aspartate aminotransferase, and alanine aminotransferase activities in fish fed the diet containing 40% protein and 8% lipid were relatively low among the dietary treatments. These results may indicate that a diet containing 40% protein and 8% lipid with P/E ratio of 84.05 mg protein/kcal would be suitable for the optimal growth, feed utilization, and health of S. graham.     

A natural infection by the red sea bream iridovirus‐type Megalocytivirus in the golden mandarin fish Siniperca scherzeri

An outbreak of a Megalocytivirus infection was found in the golden mandarin fish Siniperca scherzeri during September and October 2016, in Korea. Phylogeny and genetic diversity based on the major capsid protein (MCP) and adenosine triphosphatase (ATPase) genes showed a new strain. Designated as GMIV, this strain derived from the golden mandarin fish was suggested to belong to the red sea bream iridovirus (RSIV)‐subgroup I. Additionally, this train clustered with the ehime‐1 strain from red sea bream Pagrus major in Japan and was distinguished from circulating isolates (RSIV‐type subgroup II and turbot reddish body iridovirus [TRBIV] type) in Korea. The infection level, evaluated by qPCR, ranged from 8.18 × 10² to 7.95 × 10⁶ copies/mg of tissue individually, suggesting that the infected fish were in the disease‐transmitting stage. The diseased fish showed degenerative changes associated with cytomegaly in the spleen as general sign of Megalocytivirus infection. The results confirm that the RSIV‐type Megalocytivirus might have crossed the environmental and species barriers to cause widespread infection in freshwater fish.     

Comparative effect of advanced soy products or corn protein concentrate with porcine meal on growth,body composition,and distal intestine histology of Florida pompano,Trachinotus carolinus

The present study was designed to investigate the effects of diets containing advanced soy products (enzyme‐treated soy and fermented soy) or corn protein concentrate (CPC) in combination with porcine meal (PM) to completely replace poultry byproduct meal (PBM) on growth performance, body composition, and distal intestine histology of Florida pompano, Trachinotus carolinus. Four experimental diets were formulated to be isonitrogenous and isolipidic, to contain 400 g/kg crude protein and 80 g/kg lipid. A reference diet (PBM diet [PBMD]) contained 150 g/kg PBM and 495 g/kg soybean meal (SBM), and three test diets were formulated replacing PBM with 15 g/kg of CPC (CPC diet [CPCD]) or replacing all SBM and PBM with 535 g/kg fermented soy (fermented soybean meal diet [FSBMD]) or 451.3 g/kg enzyme‐treated soy (enzyme‐treated soybean meal diet [ESBMD]). All three test diets were supplemented with 38 g/kg of PM. Diets were fed based on a percentage of bodyweight adjusted after sampling the fish every 2 weeks to triplicate groups of Florida pompano juveniles (mean weight 8.06 ± 0.22 g). After 8 weeks of feeding, fish fed CPCD and ESBMD performed equally well in terms of final body weight, thermal growth coefficient, and percentage weight gain in comparison to fish fed PBMD. In all cases, feeding FSBMD resulted in poor feed conversion and lower feed intake compared to other treatments. Protein retention efficiency, whole‐body proximate composition, phosphorus, sulfur, potassium, magnesium, calcium, sodium, and zinc contents were not significantly influenced by the dietary treatments. The results obtained in the present histological study showed no significant differences in the thickness of serous layer, muscular layer, and submucosal layer of the intestine among treatments. Fish fed CPCD showed a significant widening of the lamina propria with an increase of cellular infiltration and higher presence of goblet cells compared to other dietary treatment. Based on these results, 451 g/kg ESBM or combination of 150 g/kg of CPC and 495 g/kg SBM supplemented with 38 g/kg PM can be utilized to develop a practical diet for juvenile Florida pompano without impacting growth, nutritive parameters, and several distal intestine health parameters.     

Effect of dietary vitamin B6 supplementation on growth and intestinal microflora of juvenile golden pompano (Trachinotus ovatus)

In order to investigate the dietary vitamin B₆ (VB₆) requirement for juvenile golden pompano, an experiment of six different diets with six dietary VB₆ levels (0, 3.75, 7.47, 10.6, 13.7 and 18.5 mg/kg) was conducted. The results indicated that the content of dietary VB₆ significantly increased weight gain rate (WGR), specific growth rate (SGR) and feed conversion ratio (FCR; p < 0.05). Golden pompano fed diet containing 7.47 mg/kg VB₆ achieved the maximum ALT, AST, GPx, hepatic VB₆ concentrations as well as the minimum MDA, however, the ALT, AST, GPx and hepatic VB₆ concentrations decreased while MDA increased with a further increase in dieatry VB₆. The highest values of GR and POD occurred at the 10.6 and 13.7 mg/kg dietary VB₆ (p < 0.05) respectively. A diet supplemented with 7.47 mg/kg VB₆ increased intestinal Na⁺, K⁺‐ATPase, Chymotrypsin, γ‐glutamyl transpeptidase, creatine kinase and amylase activities (p < 0.05). The relative abundance of Tenericutes and Bacteroidetes decreased while Proteobacteria and Firmicutes improved with an increase in dietary VB₆ levels up to 7.47 mg/kg. Quadratic regression analysis on WGR, hepatic VB₆ concentrations, AST and ALT indicated that the optimum dietary VB₆ levels for juvenile golden pompano were 8.84–9.28 mg/kg.     

Management of Bemisia tabaci biotype B with botanical and mineral oils

While the toxic effects of neem, Azadirachta indica A. Juss, on Bemisia tabaci Genn. are well documented, few studies have evaluated other oils. We compared neem, sesame, citrus, castor, vegetable and mineral oils (1% v/v) to a chemical standard thiamethoxam (0.17 g A.I./L) against B. tabaci biotype B life stages on dry bean plants Phaseolus vulgaris L. under screenhouse conditions. Oils and thiamethoxam exhibited low ovicidal activity (<10% egg mortality). However, significant mortality occurred due to the residual activity to 1st instars that emerged from treated eggs. Overall, impacts of egg treatments were greatest for thiamethoxam (77% total mortality for eggs and 1st instars) compared with oils which were statistically similar (22–29% mortality). Larvicidal effect of oils (against 2nd instars) was greater than ovicidal effects. Highest nymphal mortality (>81%) was achieved with castor, sesame, citrus and neem oils, which was significantly greater than for thiamethoxam (65% mortality). Adult whiteflies were exposed to fresh and aged spray residues, rather than being sprayed directly. In this case, comparatively lower efficacy was achieved from oil treatments compared with thiamethoxam. While some mortality was observed from fresh residues of slow drying oils (up to 41% for castor oil), no significant control from any oil residues >3 days old was observed in our tests. The different route of exposure against adults likely reduced the effectiveness of oil treatments which act directly on the cuticle. In trials with viruliferous adult whiteflies exposed to fresh residues, none of the tested products completely prevented transmission of bean golden mosaic virus (BGMV). However, we noted reduced virus severity ratings from plants pre-treated with castor and citrus oil. We conclude that castor, sesame, citrus and neem oils have the potential to be used in whitefly management programs.     

Quantitative taurine requirement for juvenile Florida pompano (Trachinotus carolinus) fed soy‐based practical diets

Florida pompano Trachinotus carolinus is an important species in which the essentiality of taurine has been demonstrated, yet a quantitative requirement has not been estimated. Two experiments were conducted where a combined twelve diets were formulated with graded levels of taurine (ranging 1.6–41.6 g/kg dry matter) and fed to juvenile pompano (initial weight 7.73 and 4.37 g in trial 1 and 2, respectively). Dose responses were observed in terms of growth, feed efficiency and whole‐body taurine content, but there was no effect on survival. Several regression models were evaluated to determine the most appropriate one to draw conclusions from. A 4‐parameter saturation kinetic model was selected to model feed efficiency, while a 5‐parameter saturation kinetic model fitted the growth data (as thermal‐unit growth coefficient, TGC). A broken‐quadratic model served to estimate a breaking point in the whole‐body taurine content, although it also showed that whole‐body taurine kept increasing even at dietary levels in far excess of the requirement. The dietary taurine requirement was estimated at 2.5 g/kg (2.0–3.3 g/kg, 95% CI, dry matter basis) based on feed efficiency, while TGC was maximized at levels between 4.9 and 31.4 g/kg dietary taurine.     

IMAGING DIAGNOSIS—USE OF RADIOGRAPHY,COMPUTED TOMOGRAPHY,AND ENDOSCOPY IN THE DIAGNOSIS OF ESOPHAGEAL PERFORATION BY AN EXTRA‐LUMINAL TRACHEAL RING PROSTHESIS IN A GOLDEN RETRIEVER

A 6‐year‐old neutered male, Golden retriever presented with regurgitation and excitement‐induced coughing. Two years prior, extra‐thoracic tracheal collapse was diagnosed and extra‐luminal tracheal ring prostheses were placed. Radiographs at presentation showed mineralized and undulant cervical tracheal cartilages. A dorsally broad‐based soft tissue opacity bulged into the caudal cervical tracheal lumen. Esophageal dysmotility and barium accumulation were identified at this level on contrast esophography. Computed tomography showed migration of a prosthetic tracheal ring, resulting in perforation of the esophagus. Hair, foreign material, and dynamic tracheal narrowing were identified on esophagoscopy and tracheoscopy, respectively. Esophagostomy and foreign body removal were performed.     

Jaw malformation of hatchery reared golden pompano Trachinotus ovatus (Linnaeus 1758) larvae

Jaw malformations of hatchery reared golden pompano Trachinotus ovatus larvae were studied from 1 day post hatch (DPH) to 31 DPH. The severity of jaw deformities was classified into three levels where ‘0’ represents normal jaw; ‘1’ is intermediate jaw malformation; and ‘2’ is severe jaw malformation. The severe jaw malformations of golden pompano larvae were clearly observed on 3 DPH. Starting from 3 DPH, both intermediate and severe jaw malformations were observed and the total incidence of jaw malformations ranged from 9.6% to 46.6%. The highest severe jaw malformation occurred on 5 DPH, and 25% larvae exhibited serve jaw malformation. On 11 DPH, jaw malformations reached the peak with 46.6% fish exhibiting jaw malformations of either category 1 or 2. On 26 DPH, the percentage of intermediate jaw malformation reached the peak value (36.4%). This was the first study reporting jaw malformation of golden pompano larvae, and the result can be used as a reference point for future research on the control of jaw malformation in golden pompano.     

亚麻酸对卵形鲳鲹幼鱼生长性能、消化酶活性及抗氧化能力的影响

探讨了饲料中不同水平的亚麻酸对卵形鲳鲹(Trachinotus ovatus)幼鱼生长性能、消化酶活性及抗氧化能力的影响。选取均体质量为(10.38±0.10)g的卵形鲳鲹幼鱼随机分配6组,每组3个平行,每个平行20尾鱼。配制6种亚麻酸质量分数分别为0.13%、0.59%、1.10%、1.60%、2.10%和2.50%的实验饲料饲喂卵形鲳鲹,每天饲喂2次,周期为56 d。结果表明,饲喂含0.59%和1.10%亚麻酸饲料的实验鱼增重率、特定生长率显著高于2.1%组和2.5%组。亚麻酸水平显著影响了实验鱼的肝体比、脏体比、腹脂率、肥满度及其成活率。0.59%组实验鱼的胃蛋白酶显著高于0.13%组和2.50%组。1.10%组的淀粉酶活性显著低于其他各组。血清总抗氧化能力和过氧化氢酶活性随着饲料中亚麻酸含量的升高呈现出先升高后降低的趋势。以特定生长率为评价指标,二次曲线回归分析得出卵形鲳鲹幼鱼对亚麻酸的最适需求量为饲料干质量的1.04%。     

基于黄金分割法的双季稻合理密植研究

为了验证水稻合理密植的黄金分割法在长江中下游双季稻区和华南双季稻区的适用性,在湖南长沙和广东怀集以生产上大面积种植且具有代表性的双季稻品种为材料,运用黄金分割法分割秆高(50、65、80、95、110 cm)得到5种预设黄金密度(67.9、40.1、26.5、18.8、14.0穴·m-2),研究不同密度下株高和秆高的变化,实际黄金密度下齐穗期部分冠层特性、干物质积累、产量及其构成。结果表明,在不同密度下,长沙水稻的株高和秆高,怀集早稻玉香油占的秆高及晚稻Y两优1号的株高和秆高变化不显著,而早稻Y两优1号株高和秆高变化显著,其余品种无一致的规律。在实际黄金密度下,长沙各品种有效和高效叶面积指数及其冠层光辐射截获率最高,或者低于最高密度处理,但冠层光辐射截获率与最高密度处理无显著差异;长沙和怀集各品种齐穗期和成熟期的干物质积累及其产量在实际黄金密度下最高,或者低于最高值,但产量与最高值差异不显著。长沙双季稻和怀集晚稻的矮秆品种(49.4~74.5 cm),其产量的主要贡献来源于有效穗数,而怀集早稻的高秆品种(80.4~84.6 cm),其产量的主要贡献来源于有效穗数和每穗粒数。本研究结果为合理、简便、精确确定水稻适宜的种植密度(即合理密植)提供了理论和实践依据。