Influence of different sources and levels of dietary protein and lipid on the growth,feed efficiency,muscle composition and fatty acid profile of Snakehead Channa striatus (Bloch, 1793) fingerling

Nine isoenergetic (18.5 kJ g⁻¹) diets were formulated, in a 3 × 3 factorial design, by varying three levels of dietary protein (350, 400 and 450 g kg⁻¹) at each of three levels of dietary lipid (65, 90 and 115 g kg⁻¹) accordingly. Each diet was hand fed two times daily for 8 weeks to triplicate homogenous groups of eight fish (average weight 3.34 ± 0.02 g) per tank connected to a recirculation system. Results showed that the feed efficiency and growth performance significantly (P<0.05) increased with increasing protein level at the two lower lipid levels (65 and 90 g kg⁻¹), respectively, as indicated by indices such as %weight gain, specific growth rate, protein efficiency ratio, feed conversion ratio and feed intake, but did not at the highest lipid level (115 g kg⁻¹). The muscle polyunsaturated fatty acids (PUFA) content declined with increasing dietary protein level at the lipid levels producing the highest growth, suggesting that the utilization of PUFA influences growth. Whereas the muscle monounsaturated fatty acids level was generally lower than the dietary levels in all the treatments tested, indicating preferential catabolism for energy, the muscle saturated fatty acids level was comparatively higher than in the diets, indicating selective deposition. Docosa hexaenoic acid (22:6n3, DHA), which was very low in the diet and in the initial fish, was higher in the muscle of some of the treatments, indicating the ability of Channa striatus to desaturate and elongate short‐chain PUFA to long‐chain HUFA, due to the availability of dietary 18:3n3 and 20:5n3 (the precursors for DHA biosynthesis). It could be concluded, based on the results of this trial, that a diet formulated to contain 65 g kg⁻¹ lipid and 450 g kg⁻¹ protein, with a gross energy of 18.5 kJ g⁻¹ and a dietary n3/n6 PUFA ratio of about 0.1, is sufficient to promote good feed efficiency and growth performance in C. striatus fingerling.     

Resolving the motional modes that code for RNA adaptation

Using a domain elongation strategy, we decoupled internal motions in RNA from overall rotational diffusion. This allowed us to site-specifically resolve a manifold of motional modes in two regulatory RNAs from HIV-1 with the use of nuclear magnetic resonance spin relaxation methods. Base and sugar librations vary on a picosecond time scale and occur within helical domains that move collectively at diffusion-limited nanosecond time scales. Pivot points are short, functionally important, and highly mobile internal loops. These spontaneous changes in RNA conformation correlate quantitatively with those that follow adaptive recognition of diverse targets. Thus, ligands may stabilize existing RNA conformations rather than inducing new ones.     

Analysing the effect of dietary prebiotics and probiotics on gut bacterial richness and diversity of Asian snakehead fingerlings using T‐RFLP method

This study was designed to evaluate the effects of three prebiotics (β‐glucan, galacto‐oligosaccharide [GOS], mannan‐oligosaccharide [MOS]) and two probiotics (Saccharomyces cerevisiae, Lactobacillus acidophilus) on the microbiome of snakehead during growth of fingerlings. In addition, the experiment evaluated the capacity of Channa striata fingerlings to retain the benefits derived from these supplements after withdrawal. Throughout the study, it was observed that supplementation with dietary prebiotics and probiotics led to significant (p < 0.05) change in gut bacterial profile and improvement in gut morphology. Terminal restriction fragment length polymorphism (T‐RFLP) was used for the comparative analysis of gut communities and all 46 of the T‐RFLP detected phylotypes were present in the Lactobacillus supplemented fish, while significantly fewer were detected in controls and other experimental supplement regimes. Histological studies and electron microscopy revealed that both the prebiotic and probiotic treated fish had significantly longer and wider villi and deeper crypts compared to the controls. The microvilli length, as evaluated with electron microscopy, was also longer in all treated fish compared to controls. Furthermore, this study is the first to report the absence of differences in sustaining the efficacies attained after intake of β‐glucan, GOS, MOS and live yeast upon post‐feeding with an unsupplemented feed, over a prolonged period.     

Coli-bacillosis in chicks in Saudi Arabia

Tropical Animal Health and Production -     

Effects of thiopentone, propofol, alphaxalone-alphadolone, ketamine and xylazine-ketamine on lower oesophageal sphincter pressure and barrier pressure in cats

The anaesthetic induction agents thiopentone, propofol and alphaxalone-alphadolone were administered to cats intravenously and ketamine and xylazine-ketamine-atropine were administered intramuscularly in order to determine their effects on gastric pressure, lower oesophageal sphincter pressure, and barrier pressure. Manometric measurements were made with a non-perfused catheter tip pressure transducer. All the anaesthetic induction agents decreased the tone of the lower oesophageal sphincter but the reduction was least with ketamine. Lower oesophageal sphincter tone was significantly higher in cats anaesthetised with either xylazine-ketamine-atropine or propofol than in cats anaesthetised with either thiopentone or alphaxalone-alphadolone. Despite a higher gastric pressure in the cats anaesthetised with ketamine rather than with the other drugs except propofol, the barrier pressure was also significantly higher in cats anaesthetised with ketamine than in cats anaesthetised with any of the other drugs except xylazine-ketamine-atropine. The risk of gastrooesophageal reflux seemed to be higher with alphaxalone-alphadolone than with thiopentone if the lower oesophageal sphincter pressure and gastric pressure are used as indicators of likely reflux.     

阿克苏拜城天山区盘羊和北山羊的分布与种群资源现状

根据2008～2009年实地考察研究结果,着重就该区2种有蹄类动物的分布、种群数量以及有关问题作概要性探讨。调查研究结果表明：（1）老虎台盘羊分布区盘羊平均密度=8.49/8=1.06只/km^2,黑英山盘羊分布区盘羊平均密度=5.34/3=1.78只/km^2。整个分布区盘羊种群数量1 488只,其中,老虎台分布区种群数量=480×1.06=509只,黑英山分布区种群数量=550×1.78=979只。（2）老虎台北山羊分布区北山羊平均密度=14.59/5=2.92只/km^2,黑英山北山羊分布区北山羊平均密度=7.01/4=1.75只/km^2。整个分布区北山羊种群数量5 604只,其中,老虎台分布区种群数量=1 200×2.92=3 504只,黑英山分布区种群数量=1 200×1.75=2 100只。以上数据为该区2种野生有蹄类动物开展狩猎与保护提供了对策性依据。     

Effects of substituting dietary fish oil with crude palm oil and palm fatty acid distillate on growth,muscle fatty acid composition and the activities of hepatic lipogenic enzymes in snakehead (Channa striatus,Bloch 1793) fingerling

Three diets were formulated to be iso‐nitrogenous (450 g kg^?1), iso‐lipidic (65 g kg^?1) and iso‐energetic (18.5 KJ g^?1), varying only in their lipid sources and designated as 100% fish oil (FO), 100% crude palm oil (CPO) and 100% palm fatty acid distillate (PFAD). Feed were hand fed to homogenous groups of 12 Channa striatus fingerlings (mean weight 3.5 ± 0.3 g) per tank in triplicate for 12 weeks, in a recirculation system. The growth performance and feed intake in the CPO and PFAD treatments were significantly (P<0.05) higher than those in the fish fed the control diet (FO), respectively, whereas the feed conversion ratio was better in PFAD than that in the other treatments respectively. The biological indices monitored (hepatosomatic index and viscerosomatic index) as well as carcass yield did not vary significantly among all the treatments respectively. The muscle fatty acid (FA) profile of fish was influenced by the composition of the diets fed, whereas no differences were recorded in the activities of the hepatic lipogenic enzymes monitored (fatty acid synthetase, citrate cleavage enzyme and malic enzyme). Whole‐body proximate composition analysis revealed that PFAD treatment, compared with others, contained significantly higher protein and ash, but lower lipid contents, although the muscle content of these nutrients was similar among all the treatments. Based on the results of this trial, CPO and PFAD could be used to partially substitute FO in the diet for C. striatus fingerling, to achieve good growth performance without any negative effects or compromising the muscle n‐3 FA composition (especially in the docosa hexaenoic acid and eicosa pentaenoic acid content).     

Effect of lipid levels on the reproductive performance of Snakehead murrel,Channa striatus

Present study aimed to determine the optimum dietary lipid level in snakehead murrel channa striatus broodstocks. Triplicate groups of fish were fed for 240 days with isonitrogenous experimental diets with increasing lipid levels (100, 140, and 180 g kg^?1), using fish oil and soybean oil as the lipid sources with the ratio of (1:1). Weight gain, GSI, fecundity, oocyte diameter and number of mature oocyte were found to be significantly higher in the group fed with diet containing 180 g kg^?1 lipid level. Muscle fatty acid profile showed a significant increase in LA (18:2n‐6), LNA (18:3n3), total PUFA, n‐6 and ArA (20:4n‐6) in fish fed with diet containing 180 g kg^?1 lipid. Increasing lipid level up to 180 g kg^?1 resulted in significant increase in PUFA (LA & LNA), lc‐PUFA (EPA, DHA, ArA), total PUFA, n‐3 and n‐6 series in ovary and liver of female C. striatus.     

Identification and partial characterization of selected proteolytic enzymes in the digestive system of giant freshwater Prawn Macrobrachium rosenbergii (De Man) Postlarvae

Biochemical assays and substrate SDS-PAGE were conducted to partially characterize and identify various types of proteases present in the digestive tract of PL₁₅ giant freshwater prawn ( Macrobrachium rosenbergii ). Casein hydrolytic assay of the enzyme extracts showed major proteolytic activities at pH 3.0, 6.0 and 9.0, while assay of preincubated enzyme extracts with phenylmethylsulphonyl fluoride (PMSF), a serine protease inhibitor produced a 33.17% reduction in alkaline protease activity. When specific inhibitors tosyl-lysine chloromethyl ketone and tosyl-phenylalanine chloromethyl ketone were used, they resulted in a reduction in activity of proteases in the enzyme extracts by 82.41% and 55.03%, respectively, confirming the presence of trypsin and chymotrypsin, while ethylenediamine tetraacetic acid produced protease activity reduction in 33.92% showing the presence of metalloproteases in the digestive tract of the prawn. Further characterization of the alkaline proteases using SDS-PAGE technique, after incubating the extract in the presence or absence of specific inhibitors, produced six bands corresponding to molecular masses of between 13.48 and 136.1 kDa; two trypsin bands of 13.48 and 36.4 kDa, three chymotrypsin bands in the range of 23.0–73.4 kDa and one for metalloprotease of 136.1 kDa, all of which were identified from a zymogram. This study suggests that protein digestion in M. rosenbergii is initiated by an acid protease followed by a combination of action of alkaline proteases: trypsin, chymotrypsin and metalloproteases.     

山羊酸奶加工工艺研究

山羊奶含有丰富的蛋白质、脂肪、乳糖、矿物质及多种维生素,Ca、P及某些生物活性物质（如cAMP,cGMP等）含量高于牛奶。采用响应曲面法研究了山羊酸奶的发酵温度、加糖量、球杆菌比例和接种量。结果表明：在38℃,蔗糖添加量6％,嗜热链球菌接种量1．5％,保加利亚乳杆菌接种量0．5％的条件下,山羊酸奶品质最好。