Chemical Composition and Ruminal Dry Matter and Crude Protein Degradability of Spineless Cactus

The objective of this study was to determine ruminal degradability of the dry matter (DM) and crude protein (CP) of 10 varieties of spineless cactus (Opuntia spp.) grown in north‐eastern Brazil. Two ruminally fistulated steers were used in a randomized complete block design. Ash, CP, acid detergent fiber, and acid detergent lignin levels ranged from 10.4 to 13.3 %, 6.2–7.7 %, 19.8–24.8 % and 3.4–5.4 %, respectively. Relative to the other cactus varieties, Redonda had the highest (P < 0.05) in situ soluble DM fraction and effective DM degradability. No differences in effective DM degradability were observed between the other cactus varieties. In situ soluble CP fraction ranged from 1.7 % of CP for the 69 IPA/UFRPE variety to 11.1 % of CP for the Gigante variety. Slowly degradable CP fraction and its rate of degradation were similar among the cactus varieties (average 90 % of CP and 9 % h^?1, respectively). The cactus variety 69 IP/UFRPE had a lower (P < 0.05) effective ruminal CP degradability (ECPD) than the other varieties, which had a similar ECPD (average 66 % of CP). It was concluded that differences in ruminal degradability exist between cactus varieties, with more variations observed for ruminal DM than for CP degradability.     

Normal features of superficial nondesquamating cells of the rabbit corneal epithelium assessed by scanning electron microscopy

Objective To quantitatively assess surface features of corneal epithelial cells with particular emphasis on regional differences in cell size or shape. Animals studied Female New Zealand White rabbits, aged 11–12 weeks. Procedures Animals were exposed to a light : dark cycle of 14 : 10 h for 2 weeks and then the corneas prepared for scanning electron microscopy (SEM) at 1500 h. Images were taken at central location (C), mid‐periphery (MP), and periphery (P) of the cornea. On prints at 5000×, cell–cell borders were marked, and long (L) and short (S) dimensions measured, and the surface ring‐shaped features outlined and counted. Results Across the epithelial surface cells had from 3 to 11 bordering cells (sides), with 5‐sided cells being more common (mean 32.7 ± 11.3%, SD). L dimensions averaged 26.7, 30.9, and 33.9 µm at the C, MP, and P locations, while S dimensions were 18.5, 21.8, and 24.0 µm, respectively. The L : S ratio was1.523, with averages of 1.567, 1.501, and 1.487 at the three locations. Using an averaged cell dimension, cell density was estimated and found to be 7376, 4405, and 3071 cells/mm² at C, MP, and P locations. Almost all cells were decorated with ring‐shaped features (craters), with the number increasing in relation to cell size and were much higher on more peripheral cells. Conclusions The non‐exfoliating corneal epithelial surface is composed of flat polygonal cells often with 5‐sides cells, which are progressively larger towards the peripheral cornea and more decorated with ring‐shaped features.     

Effects of forage source and particle size on chewing activity,ruminal pH,and saliva secretion in lactating Holstein cows

The present study investigated the effects of dietary forage source (quality) and particle size on chewing activity, saliva secretion, and ruminal pH. Twelve multiparous lactating Holstein cows, four of which were ruminally cannulated, were used in a replicated 4 × 4 Latin square experimental design with a 2 × 2 factorial arrangement of treatments. Cows fed wild‐rye hay diets had longer daily eating times than cows fed oaten hay diets. Treatments had no effect on ruminating time; therefore, resting time varied inversely to eating time. Neither the rate nor the amount of saliva secretion while eating, ruminating, or resting was affected by diet, resulting in similar total daily saliva secretions across treatments (231 L/day). Total volatile fatty acids (VFAs) in the ruminal fluid from animals fed oaten hay diets were higher than those from animals fed wild‐rye hay diets; further, VFAs increased with decreasing forage particle size (FPS). Consistent with elevated VFA concentrations, reducing FPS and including oaten hay in the diet decreased mean ruminal pH and increased the daily time of ruminal pH under 5.8. Results of this study suggest that forage source and particle size affect ruminal pH might be via variations in VFA production rather than increased salivary recycling of buffering substrates.     

The effect of central sympathectomy by 6-hydroxydopamine (6-OHDA) on the response to morphine in conscious sheep

When morphine, an opioid -agonist, was administeredin vivo into the third cerebral ventricle (ICV) of conscious sheep at 20 and 40 µg/kg body weight, it caused psychomotor excitability for 2–3 h and a significant decrease in the reticuloruminal frequency for 45 min and in the mean amplitude of the primary contractions for 65 min. From 60 min after infusion, the same doses of morphine caused a significant increase in the average amplitude of the contractions for 45 min. This suggests that an inhibitory -opioid acceptor is involved in the central control of forestomach motility and general behaviour in sheep. All the effects of morphine were completely prevented by pretreatment with 18.2 µg/kg body weight 6-OHDA ICV. These results suggest that both morphine-induced inhibition of rumen motility and psychomotor excitability are due to central noradrenergic descending system activation. The exact location of the noradrenergic system remains to be determined.     

Does virginiamycin supplementation affect the metabolism and performance of Nellore bulls grazing under low and high gain rates?

This study aimed to evaluate the effect of virginiamycin on the metabolism and performance of growing Nellore bulls under low and high gain rates on pasture. In experiment 1, 80 Nellore bulls (age = 12 ± 2 months, body weight = 258 ± 15 kg) were assigned to 16 paddocks in a 2 × 2 randomized block factorial arrangement. In experiment 2, 12 cannulated Nellore bulls were assigned to three 4 × 4 balanced Latin squares. The factors were: (1) mineral salt without or with virginiamycin, and (2) low or high gain rate. No interaction was noted between factors (p > .10). Animals fed virginiamycin had greater average daily gain (14%, p < .01), body weight (11 kg, p = .05), plasma nonesterified fatty acid (20%, p < .01), serum calcium concentration (2.62%, p = .04), and total protozoa (p = .03) and had the same bacterial proportion (p > .27). Animals with a low gain rate had greater serum urea concentration (19.6%, p < .01) and ruminal ammonia nitrogen (62%, p < .01). Thus, virginiamycin increases the performance and changes the metabolism of growing Nellore bulls under low and high gain rates on pasture.     

冬季补饲对妊娠后期藏母羊瘤胃挥发性脂肪酸、 微生物群落结构和羔羊发育的影响

为了研究冬季补饲对妊娠期藏母羊瘤胃挥发性脂肪酸(volatile fatty acid,VFA)、微生物区系及羔羊生长发育影响.采用单因子试验设计,随机选择健康藏母羊440只,分为2组.对照组(control check,CK)为放牧饲喂,处理组(test,T)在放牧基础上,每只母羊补饲0.1 kg·d-1精料补充料,试验期为45 d(配种后106～150 d).试验结束后,从处理组和对照组中随机选择5只和6只母羊屠宰后分析瘤胃挥发性脂肪酸和细菌菌群组成.同时测定新生羔羊的生长发育指标.结果 表明:(1)处理组羔羊的体重、体高和胸围显著高于对照组(P＜0.05);(2)处理组瘤胃液总挥发性脂肪酸(Total volatile fatty acids,TVFA)、丙酸和丁酸含量显著高于对照组(P＜0.05),同时乙酸和异丁酸显著低于对照组(P＜0.05);(3)两组母羊瘤胃微生物在门和属水平上组成相似,拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)以及疣微菌门(Verrucomicrobia)为优势菌门;而普雷沃菌属-1(Prevotella l)、理研菌科RC9肠道群(Rikenellaceae-RC9-gut-group)、普雷沃氏菌科-UCG-001(Prevotellaceae-UCG-001)为优势菌属;(4) Alpha多样性指数中,对照组的Shannon指数显著高于处理组(P＜0.05),说明对照组瘤胃微生物多样性优于处理组;(5)瘤胃微生物功能预测发现,两组母羊瘤胃微生物主要富集于复制和修复(Replication and Repair)、碳水化合物代谢(Carbohydrate Metabolism)和信号转导(Signal Transduction).综上,妊娠后期藏母羊的冬季补饲能够为胎儿的生长发育提供必要的营养需求,同时提高母羊瘤胃液中TVFA、丙酸和丁酸含量,但在一定程度上影响了瘤胃细菌的多样性.     

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.     

CNCPS研究综述——瘤胃发酵

康奈尔净碳水化合物-蛋白质体系(CNCPS)是在综合了有关研究瘤胃发酵的最新研究成果和理论的基础上,结合计算机技术形成的一套新的技术体系,在生产中体现了很好的实用性和优越性。通过阐述CNCPS对瘤胃微生态、瘤胃微生物、瘤胃微生物的组成、瘤胃发酵和过瘤胃、氮损失和内源氮循环的研究,从该体系的最初研究出发,揭示该体系的基本框架,为深入理解和应用CNCPS提供参考。     

中药复方对山羊的影响:Ⅳ·瘤胃内环境参数

试验旨在研究中药复方对山羊瘤胃内环境参数的影响。选择6头健康的体重相近的安装有永久性瘤胃瘘管的周岁大足黑山羊羯羊,按3×3重复拉丁方试验设计。对照组饲喂基础日粮,2个处理组分别在基础日粮上给每头羊日喂15 g复方Ⅰ和复方Ⅱ(由藿香、苍术、黄柏和生石膏等中药按不同比例组成)。结果表明:2种复方对山羊瘤胃pH及氨氮浓度均无显著影响(P>0.05);复方Ⅰ能极显著提高山羊瘤胃内丁酸浓度及丁酸占总挥发性脂肪酸的比例(P<0.01),显著提高山羊瘤胃内乙酸和总挥发性脂肪酸等浓度(P<0.05),而复方Ⅱ仅能显著提高山羊瘤胃内丁酸浓度(P<0.05)。结果提示,2种复方均能改善山羊瘤胃内环境状况,且复方Ⅰ作用效果优于复方Ⅱ。     

海蛰的生殖与受精——1.排卵方式的探讨

作者对海蛰卵巢进行了解剖、组织切片与扫描电镜观察,发现卵巢为褶叠型,一端与胶质膜相连,另一端游离。胶质膜由透明状胶质细胞所构成,外有一层纤毛细胞,靠近胶质膜一侧的卵巢为单层上皮组成的生殖上皮,胶质膜与卵巢生殖上皮间由胶质细丝连接,形成与胃腔相通的生殖腔隙。生殖上皮在生殖季节中变化很大,它首先完成发生卵原细胞的功能,随后局部解体出现透明小区,当卵巢成熟时生殖上皮细胞是区域性弥散,卵子裸露,出现分批排卵现象.海蛰排卵方式是以大量卵子成片分批区域性排放为主,但也存在单个卵子排出的现象。