Effects of supplementation with narasin,salinomycin, or flavomycin on performance and ruminal fermentation characteristics of Bos indicus Nellore cattle fed with forage-based diets

The aim of the present study was to evaluate the inclusion of narasin, salinomycin, or flavomycin for 140 d on ruminal fermentation parameters, apparent nutrient digestibility, and performance of Nellore cattle offered a forage-based diet. In experiment 1, 32 rumen-cannulated Bos indicus Nellore steers [initial body weight (BW) = 220 ± 12.6 kg] were assigned to individual pens in a randomized complete block design according to their initial shrunk BW. Within block, animals were randomly assigned to 1 of 4 treatments: (1) forage-based diet without feed additives (CON; n = 8), (2) CON diet plus 13 ppm of narasin (NAR; n = 8), (3) CON diet plus 20 ppm of salinomycin (SAL; n = 8), or (4) CON diet plus 3 ppm of flavomycin (FLA; n = 8). The experimental period lasted 140 d and was divided into 5 periods of 28 d each. The inclusion of feed additives did not impact (P ≥ 0.17) dry matter intake (DMI), nutrient intake, and apparent total tract digestibility of nutrients. Nonetheless, steers fed NAR had lower (P < 0.01) molar proportion of acetate compared with CON, SAL, and FLA steers, whereas ruminal acetate tended to be greater (P < 0.09) for SAL vs. CON and FLA, but did not differ (P = 0.68) between CON vs. FLA steers. Ruminal propionate was the highest (P < 0.01) for steers fed NAR and did not differ (P > 0.20) between CON, SAL, and FLA. Consequently, NAR steers had the lowest (P < 0.01) Ac:Pr ratio, whereas Ac:Pr did not differ (P > 0.18) among CON, SAL, and FLA. Total volatile fatty acids were greater (P < 0.04) for NAR and CON vs. SAL and FLA, but did not differ (P > 0.67) among NAR vs. CON and SAL vs. FLA. In experiment 2, 164 Nellore bulls (initial shrunk BW = 299 ± 2.5 kg) were assigned to feedlot pens for 140 d in a randomized complete block design. Within block (n = 10), animals were randomly assigned to the same treatments used in experiment 1. Average daily gain was greater (P < 0.01) in NAR vs. CON, SAL, and FLA bulls, and did not differ (P > 0.12) between CON, SAL, and FLA bulls. Bulls fed NAR had greater (P < 0.02) DMI (as kg/d or % BW) and final shrunk BW compared with CON, SAL, and FLA bulls, whereas DMI and final shrunk BW did not differ (P > 0.26) between CON, SAL, and FLA bulls. Feed efficiency, however, was not impacted (P = 0.51) by any feed additives used herein. Collectively, narasin was the only feed additive that benefited performance and ruminal fermentation of Nellore animals fed a forage-based diet.     

小肽与酵母培养物对舍饲牦牛瘤胃微生物多样性和发酵参数的影响

为研究添加小肽与酵母培养物对舍饲育肥牦牛瘤胃微生物多样性和发酵参数的影响,试验选取36头年龄为4周岁左右、体重水平相当、健康状况良好的麦洼牦牛,随机分为4个处理组,对照组饲喂全混合日粮(TMR),试验Ⅰ、Ⅱ、Ⅲ组在TMR基础上分别添加1%酵母培养物、0.75%小肽、1%酵母培养物+0.75%小肽。试验结果表明:(1)四个处理组的优势菌门均为拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)、互养菌门(Synergistests)和变形菌门(Proteobacteria)。小肽和酵母培养物的添加显著降低了变形菌门的相对丰度(P<0.05),提高了拟杆菌门和互养菌门的相对丰度,但差异不显著(P>0.05)。从属水平分析,拟杆菌科的BS11菌属(Bacteroidetes BS11 gut group)、理研菌科RC9菌属(Rikenellaceae RC9 gut group)、普雷沃氏菌属(Prevotella 1)、克里斯滕森菌科的R7菌属(Christensenellaceae R 7 group)为四个处理组共有优势菌属。添加小肽和酵母培养物,显著提高了理研菌科RC9菌属、普雷沃氏菌属、疣微菌科UCG-010菌属(Ruminococcaceae_UCG-010)、帕匹杆菌属(Papillibacter)、柔膜菌纲RF9菌属(Mollicutes_RF9)的相对丰度(P<0.05)。(2)小肽与酵母培养物单独添加或同时添加对瘤胃中pH和氨态氮(NH3-N)浓度无显著影响(P>0.05);降低了瘤胃中乙酸浓度,但差异不显著(P>0.05);1%酵母培养物组和1%酵母培养物+0.75%小肽组显著提高了瘤胃中丙酸浓度(P<0.05),0.75%小肽组虽提高了瘤胃中丙酸浓度,但差异不显著(P>0.05);小肽与酵母培养物单独添加或同时添加都显著降低了乙/丙(P<0.05),表明瘤胃发酵从乙酸型向丙酸型转变,有利于能量利用效率的提高。综上所述,小肽与酵母培养物单独或同时添加都促进了瘤胃有益菌群生长,使瘤胃发酵从乙酸型向丙酸型转变,提高了能量利用效率,小肽与酵母培养物合用具有叠加效应。     

复合营养性添加剂对缓解蛋鸡运输应激效果研究

为研究复合营养性添加剂对长距离运输后育成期蛋鸡生长性能、血液生化和血液激素水平的影响,采用2×2双因子试验设计,主效应分别是时间点(处理前、处理后)和复合营养性添加剂(0、1 g/kg)。随机选择15周龄长距离运输后的罗曼蛋鸡180只,随机分为2个组,每个组5个重复,每个重复18只。对照组饲喂基础日粮,试验组在基础日粮中添加1 g/kg的复合营养性添加剂。试验饲喂期为5 d。结果显示:①复合营养性添加剂有降低血液促肾上腺皮质激素的趋势(P=0.09),显著降低了血液三碘甲状腺原氨酸的含量和甲状腺素的含量(P<0.05);②复合营养性添加剂显著(P<0.05)提高了运输高应激后蛋鸡采食量,进而提高了蛋鸡体重均匀度;③运输应激极显著(P<0.01)提高血液谷草转氨酶、肌酐和乳酸脱氢酶水平,极显著(P<0.01)降低肌酸激酶水平。复合营养性添加剂极显著(P<0.01)降低血液谷草转氨酶水平。研究表明:运输应激会造成育成期蛋鸡采食量降低,体重均匀度下降,添加复合营养性添加剂能显著缓解蛋鸡运输应激。     

饲粮不同比例青贮玉米对仔鹅生长性能、屠宰性能、肉品质及血清生化指标的影响

本试验旨在研究饲粮中添加不同比例全株青贮玉米对仔鹅生长性能、屠宰性能、肉品质及血清生化指标的影响,为全株青贮玉米在肉鹅养殖上的应用提供依据。试验选取健康、平均体重为982～985 g的28日龄三花鹅280只,随机分为4组,每组7个重复,每个重复10只仔鹅。对照组饲喂基础饲粮,试验组分别饲喂添加8%、16%、24%全株青贮玉米的试验饲粮,试验期为42 d。记录28、42、56、70日龄时鹅的体重（BW）和耗料量,计算平均日增重（ADG）、平均日采食量（ADFI）及料重比（F/G）; 70日龄时,每个重复选择2只接近平均体重的仔鹅屠宰,测定屠宰性能、肉品质和血清生化指标。结果表明：与对照组相比,在28～42日龄时,16%试验组的仔鹅ADG和ADFI显著升高（P<0.05）;在42～56日龄时,8%试验组的仔鹅ADFI显著升高（P<0.05）;在56～70日龄时,试验组的仔鹅ADG、ADFI和F/G均无显著差异（P>0.05）;28～70日龄的ADG和添加水平呈二次曲线关系（P<0.05）,达最高ADG水平的添加量为9.01%。与对照组相比,70日龄时,24%试验组的仔鹅体重显著降低（P<0.05）;各试验组的全净膛率和屠宰率显著降低（P<0.05）;屠宰率和添加水平呈二次曲线关系（P<0.05）,达最低屠宰率的添加水平为14.93%;各试验组仔鹅的肉品质无显著差异（P>0.05）。与对照组相比,8%试验组的仔鹅的血清甘油三酯含量显著降低（P<0.05）。综上所述,在本试验条件下,适量添加全株青贮玉米可提高仔鹅的生长性能,降低血清中的甘油三酯含量,对肉品质无显著影响,对屠宰性能有一定的负面影响,根据饲粮中添加全株青贮玉米的水平对ADG的最高限量和对屠宰性能的最低限量,建议在饲粮中的添加水平为9.01%～14.93%。     

High-speed centrifugation of extender of freeze-thaw boar semen

In semen cryopreservation, egg yolk is still widely used as a non-penetrating cryoprotectant. Much has been developed in the search for alternatives for this biological product. This work aimed to evaluate the processed egg yolk through ultracentrifugation and/or sonication in the cryopreservation of swine semen. Twenty-seven semen doses were purchased from a commercial boar stud and processed for cryopreservation using egg yolk lactose 11% (control) extender, processed using two different methods: high-speed centrifugation and sonication. Then, they were submitted to freeze-thawing protocol and were assessed for kinematic and cell structural parameters. Samples in which extenders underwent centrifugation had better results in velocity parameters, meanwhile those that only sonication was performed had poorest results in this parameter. The preservation of the membrane and mitochondria structure had better results when the diluent was only centrifuged in comparison with the other treatments. Therefore, centrifugation of extender containing egg yolk is important for better cryopreservation of swine semen.     

Reproductive performance and seasonal plasma sex steroid and metabolite levels in a captive wild broodstock of brill Scophthalmus rhombus L.

This study reports egg production by captive wild brill Scophthalmus rhombus, a potential new flatfish species for Southern Europe‐Mediterranean mariculture, as well as seasonal plasma levels of 17β–estradiol, testosterone, 11–ketotestosterone, proteins, triglycerides, glucose and lactate. A mean egg production of 102 800 eggs kg body weight⁻¹ was achieved during the 2005 spawning period (January–March), although a continuous egg supply could only be obtained from some females, which had a higher relative fecundity (261 019±10 393 eggs kg⁻¹) with 12–17 eggs batches released at a mean interval of 3.4 days. Most eggs were obtained with water temperatures ranging from 12 to 14°C, and under increasing temperatures (up to 2.9°C). Potential egg viability (70.1±2.9%), fertilization (72.2±3.4%) and hatching rates (31.9±3.9%) showed high variability, with potential viability tending to decrease as the water temperature increased (mainly between 16 and 17°C) and 0% hatching above 16.6°C. The endocrine changes that brill underwent during late gametogenesis, spawning and postspawning periods were similar to those reported in other Pleuronectiformes. This study establishes an important basis for further research on the biology and physiology of brill reproduction, directed towards the optimization of the breeding techniques used currently.     

Success of nursing ide (Leuciscus idus, L.) fry related to the period of feeding with live food

The ide Leuciscus idus (Linnaeus 1758) belongs to autochthonous, less frequent and vulnerable fish species in the frame of ichthyofauna of the Czech Republic. It was the reason for testing the possibility of captive breeding and production of fry in a controlled environment. The goal of this paper was to find the optimal transfer time of ide larvae from live food (Artemia salina nauplii) to dry starter feed providing good survival and growth. At the end of the experiment, high values of cumulative survival (in percentages) and individual weight (in milligrammes) were found for ide fry in groups D (90.6%, 178.6 mg; 15 days A. salina + 10 days starter feed), A (89.9%, 169.9 mg; A. salina only) and C (88.6%, 160.4 mg; 10 days A. salina + 15 days starter feed). Significantly lower values of the given parameters were found in group B (57.1%, 92.6 mg; 5 days A. salina + 20 days starter feed), and the lowest ones were in group E (29.8%, 75.6 mg; starter feed only). Mean values of the level of ontogenesis at the end of the experiment in fry of A–E groups were analogous to length and weight growth. Groups D, C and A consisted of juveniles only (J1, J2), and groups B and E consisted of larvae and juveniles (L4, L5, L6, J1, J2). Condition and production parameters [Fulton’s coefficient of condition (FWC), total length (TL), weight (w), specific growth rate (SGR), food conversion ratio (FCR), cumulative survival] and relationships between basic lengths TL, fork length (FL) and standard length (SL) were evaluated.     

重金属离子对鱼类血液指标影响的研究

此次试验的目的是研究鲤鱼经短时间高浓度的重金属溶液的暴露,几项血液学指标的变化情况。鲤鱼分别在铅、铜、镉、锌溶液中暴露3h后,随即转置于清洁水中,并立即随机抽取血液样本,以后隔天抽样,到第96h抽样后完成。结果发现:在红细胞系中,红细胞比容短暂升高,红细胞计数正常,红细胞体积发生临时膨胀,原红细胞比率增加。在白细胞系中,由于淋巴细胞数量的下降导致白细胞计数减少,嗜中性白细胞比率增加。结果表明:即使是在高浓度的重金属离子溶液中短时间的暴露,也会诱发鱼体的应激反应,机体加大能量的消耗来满足红细胞系的适应性变化,白细胞系内则出现了明显的免疫抑制反应,从而导致它们对疾病抵抗力的降低。     

Efficacy of fermented prawn shell waste as a feed ingredient for Indian white prawn, Fenneropenaeus indicus

Prawn shell waste collected from shrimp‐processing plants in Cochin, India, was subjected to fermentation using 20 chitinoclastic and proteolytic/non‐proteolytic bacterial strains. The products generated were analysed for protein, lipid, total sugars, N‐acetyl glucosamine, free amino acids and ash. Shrimp diets were prepared using these 20 fermented products and a control diet using raw prawn shell waste. Feeding experiment was conducted with postlarvae (PL21) of Indian white prawn, Fenneropenaeus indicus for a period of 21 days. Biogrowth parameters such as mean weight gain, feed conversion ratio, specific growth rate and protein efficiency ratio were estimated and the animals were challenged with white spot virus orally via diet. Enhanced growth could be observed in prawns fed F134 and F124, incorporated with the fermentation products generated using Bacillus spp., C134 and C124 respectively. The percentage survival of prawns after 7 days of challenge was found to be highest for groups fed diet F111 incorporated with fermentation product generated using Bacillus sp. These products of bacterial fermentation hold promise as growth enhancers and immunostimulants in aquaculture.     

Environmental risk factors associated with amoebic gill disease in cultured salmon, Salmo salar L., smolts in Ireland

A 2-year study was carried out on amoebic gill disease (AGD) involving monthly samples of 1+ Atlantic salmon, Salmo salar L., smolts, histological assessment of the gills and analysis of environmental data. Gill pathology was seen before amoebae could be detected microscopically. These changes in gill integrity were associated with marine environmental conditions, particularly elevated ammonium, nitrite and chlorophyll levels. The results suggest that the environmental changes predispose salmon to colonization by amoebae and ciliates. High densities of histophagous scuticociliates were observed in the gills during periods of advanced gill pathology. A number of different amoebae were observed in close association with gill pathology. Neoparamoeba was not seen in high densities, nor was it associated with gill pathology, indicating that Neoparamoeba may not be the primary agent of the AGD in Irish salmonid culture.