Effects of supplementing rare earth element cerium on rumen fermentation,nutrient digestibility,nitrogen balance and plasma biochemical parameters in beef cattle

The objectives of the trial were to investigate the effects of supplementing rare earth element (REE) cerium (Ce) on rumen fermentation, nutrient digestibility, methane (CH₄) production, nitrogen (N) balance and plasma biochemical parameters in beef cattle. Four Simmental male cattle, aged at 14 months, with initial liveweight of 355 ± 8 kg and fitted with permanent rumen cannulas, were used as experimental animals. The cattle were fed with a total mixed ration (TMR) composed of concentrate mixture and corn silage. Four levels of cerium chloride (CeCl₃·7H₂O, purity 99.9%), that is 0, 80, 160 and 240 mg CeCl₃/kg DM, were added to basal ration in a 4 × 4 Latin square design. Each experimental period lasted 15 days, of which the first 12 days were for pre‐treatment and the last 3 days were for sampling. The results showed that supplementing CeCl₃ at 160 or 240 mg/kg DM increased neutral detergent fibre (NDF) digestibility (p < 0.05) and tended to increased acid detergent fibre (ADF) digestibility (p = 0.083). Supplementing CeCl₃ at 80, 160 or 240 mg/kg DM decreased the molar ratio of rumen acetate to propionate linearly (p < 0.05). Supplementing CeCl₃ at 160 or 240 mg/kg DM decreased total N excretion, urinary N excretion and increased N retention (p < 0.05), increased excretion of total urinary purine derivatives (PD) (p < 0.05) and decreased CH₄/kg DMI (p < 0.05). In conclusion, supplementing CeCl₃ at 160 or 240 mg/kg DM in the ration of beef cattle increased the digestibility of NDF, decreased the molar ratio of rumen acetate to propionate, increased N retention and microbial N flow and decreased CH₄/kg DMI.     

酵母培养物对肉牛生长性能、营养物质表观消化率及瘤胃发酵参数的影响

试验研究日粮中添加酵母培养物对西门塔尔杂交牛生长性能、营养物质表观消化率、瘤胃发酵参数及抗氧化功能的影响.选取体重相近、健康的西门塔尔杂交肉牛80头,随机分为5组,每组8个重复,每个重复2头肉牛.对照组肉牛饲喂基础日粮,试验组(A、B、C、D)依次在基础日粮中添加50、100、150、200 g/(头·d)的酵母培养物...     

甜菜粕替代玉米对肉牛生长性能及瘤胃发酵成分的影响

文章旨在研究日粮添加不同水平甜菜粕替代玉米对肉牛生长性能、瘤胃发酵能力及营养物质表观消化率的影响。试验选择初始体重为(237.2±24.5)kg的肉牛36头,随机分为4组,每组9头牛,每头牛作为1个重复,试验共进行20周。试验基础日粮以玉米和青贮高粱为主,处理组分别用33%、67%和100%甜菜粕等量替代玉米。结果:试验期间肉牛总增重和日增重随甜菜粕替代水平的升高表现为显著二次曲线效应(P<0.05),料比表现为显著二次曲线降低(P<0.05)。日粮添加甜菜粕显著提高肉牛瘤胃pH(P<0.05),33%甜菜粕替代玉米组瘤胃氨氮含量最高(P<0.05);随着日粮甜菜粕添加水平的升高,总脂肪酸、乙酸、丁酸含量及乙酸与丙酸比值表现为显著线性升高(P<0.05),而丙酸和异丁酸含量表现为显著线性降低(P<0.05)。有机物、粗蛋白质、中性洗涤纤维、酸性洗涤纤维和纤维素摄入量随日粮甜菜粕水平的升高表现为显著二次曲线增加效应(P<0.05),而粗脂肪摄入量表现为显著二次曲线降低效应(P<0.05)。有机物、中性洗涤纤维、纤维素和半纤维素表观消化率随甜菜粕水平的升高表现为显著线性升高(P<0.05)。血清肌酸酐、胆固醇水平随甜菜粕添加水平的升高表现为显著线性降低(P<0.05),而血清尿素氮、甘油三酯、IGF-1、皮质醇和T4含量表现为显著二次曲线升高效应(P<0.05)。结论:在本试验条件下,肉牛日粮用甜菜粕替代玉米可有效提高营养物质的消化率,改善肉牛瘤胃的发酵能力,在不损害动物健康的前提下提高日增重,降低料肉比,其适宜替代水平为67%。     

6种常用饲料原料在肉牛瘤胃内降解规律的研究

选用3头体重相近的安装有永久性瘤胃瘘管的科尔沁肉牛,采用尼龙袋法测定玉米面、压片玉米、啤酒糟、玉米酒糟、蚕豆和豌豆壳6种饲料原料在肉牛瘤胃内干物质(DM)、粗蛋白(CP)、淀粉的瘤胃降解率。结果显示:6种饲料原料的DM、CP的肉牛瘤胃有效降解率,压片玉米与玉米面显著高于蚕豆、豌豆壳、玉米酒糟和啤酒糟(P<0.05),压片玉米与玉米面差异不显著(P>0.05);淀粉的肉牛瘤胃有效降解率大小顺序依次为蚕豆、压片玉米、玉米面、豌豆壳、玉米酒糟和啤酒糟。试验表明,蚕豆和压片玉米、玉米面的瘤胃降解率较高,玉米酒糟与豌豆壳居中,啤酒糟相对较差。     

壳聚糖对肉牛生长性能及营养物质消化率的影响

试验旨在研究壳聚糖(chitosan,CHI)对肉牛生长性能及营养物质表观消化率的影响。选择体重、月龄接近,健康无病的24头西门塔尔育肥公牛,随机分为3个日粮处理组,每组8头牛,饲养试验分前、中、后三期,每期28 d,共84 d。三组日粮分别是在基础日粮中添加0、500和1 000 mg/kg的壳聚糖配制而成。结果表明:试验全期500 mg/kg壳聚糖组的平均日增重(ADG)和日采食量(ADFI)最高、料肉比(F/G)最低;日粮添加500 mg/kg壳聚糖可提高肉牛干物质、蛋白质、能量和钙表观消化率。说明日粮中添加500 mg/kg壳聚糖可提高肉牛营养物质的消化率,进而促进肉牛的生长。     

竹叶提取物对肉牛生产性能、瘤胃发酵特征及微生物数量的影响

试验研究竹叶提取物对肉牛生产性能、瘤胃发酵特征及微生物数量的影响.选取24头6月龄、体重(259.30±12.17) kg的西门塔尔杂交公牛,随机分为4组,每组6个重复.各组肉牛日粮中分别添加0(对照组)、40、80、120 g/d竹叶提取物,试验期180 d.结果 显示,80 g/d组肉牛的平均日增重和平均干物质采食...     

Effects of dietary crude protein and tannic acid on nitrogen excretion,urinary nitrogenous composition and urine nitrous oxide emissions in beef cattle

Two consecutive trials were carried out to study the effects of dietary crude protein (CP) and tannic acid (TA) on nitrogen (N) metabolism of beef cattle and consequently, the N₂O emissions from the urine of cattle. In Trial I, eight growing castrated cattle were used as the experimental animals. Two levels of dietary CP (110.6 and 135.7 g/kg dry matter [DM]) and two levels of TA (0 and 16.9 g/kg DM) were allocated in a replicated 2 × 2 crossover design. In Trial II, the N₂O emissions from the urine of cattle collected from Trial I were determined using the static incubation technique. An interaction between dietary CP and TA on the urinary N excretion (p < .05) was found but not on the N₂O‐N emission of cattle urine. Increasing dietary CP level from 110.6 g/kg DM to 135.7 g/kg DM increased the total N excretion (p < .001), the N retention (p < .05) and the ratio of urinary urea‐N/urinary N (p < .01), did not affect the N use efficiency (NUE; p > .05) and shifted the N excretion from faeces to urine. Increasing the dietary CP level increased the N₂O‐N emission of cattle urine. Dietary addition of TA decreased the urinary excretions of urea (p < .001) and shifted the N excretion from urine to faeces, did not affect the NUE of beef cattle (p > .10), and decreased the N₂O‐N emission of cattle urine. Pyrogallol and resorcinol of the TA metabolites were detected in urine with dietary addition of TA. Feeding beef cattle with relatively low CP level and adding TA in rations are effective approaches to mitigate the N₂O‐N emissions from cattle urine.     

Effects of traditional Chinese medicine formula on ruminal fermentation,enzyme activities and nutrient digestibility of beef cattle

This study was conducted to evaluate effects of traditional Chinese medicine formula (TCMF) combined with several herbs on ruminal fermentation, enzyme activities and nutrient digestibility. Twenty finishing bulls were assigned to control or different TCMFs (Yufeisan‐1, ‐2, ‐3; 2.5% dry matter (DM) in concentrate). Results showed that DM intake was higher (P < 0.05) in the Yufeisan‐3 group than others. Compared to control, apparent digestibility of crude protein and neutral detergent fiber were increased (P < 0.05) by Yufeisan‐3. No changes were observed in ruminal pH, concentrations of ammonia‐N, microbial crude protein and total volatile fatty acid, whereas ratio of acetate to propionate was lower (P < 0.05) and propionate proportion tended to be higher (P < 0.1) in three TCMFs than control. Ruminal xylanase (P = 0.061) and carboxymethylcellulase (P < 0.05) activities were higher in Yufeisan‐3 than control. No changes were observed in abundance of total bacteria, fungi and protozoa, whereas Fibrobacter succinogenes (P = 0.062) and Ruminococcus flavefaciens (P < 0.05) were increased and total methanogens was reduced (P = 0.069) by Yufeisan‐3 compared to control. Yufeisan‐3 improved nutrient digestibility and ruminal enzyme activity, and modified fermentation and microbial community, maybe due to the presence of Herba agastaches, Cortex phellodendri and Gypsum fibrosum.     

Effect of divergence in residual methane emissions on feed intake and efficiency,growth and carcass performance,and indices of rumen fermentation and methane emissions in finishing beef cattle

Residual expressions of enteric emissions favor a more equitable identification of an animal’s methanogenic potential compared with traditional measures of enteric emissions. The objective of this study was to investigate the effect of divergently ranking beef cattle for residual methane emissions (RME) on animal productivity, enteric emissions, and rumen fermentation. Dry matter intake (DMI), growth, feed efficiency, carcass output, and enteric emissions (GreenFeed emissions monitoring system) were recorded on 294 crossbred beef cattle (steers = 135 and heifers = 159; mean age 441 d (SD = 49); initial body weight (BW) of 476 kg (SD = 67)) at the Irish national beef cattle performance test center. Animals were offered a total mixed ration (77% concentrate and 23% forage; 12.6 MJ ME/kg of DM and 12% CP) ad libitum with emissions estimated for 21 d over a mean feed intake measurement period of 91 d. Animals had a mean daily methane emissions (DME) of 229.18 g/d (SD = 45.96), methane yield (MY) of 22.07 g/kg of DMI (SD = 4.06), methane intensity (MI) 0.70 g/kg of carcass weight (SD = 0.15), and RME 0.00 g/d (SD = 0.34). RME was computed as the residuals from a multiple regression model regressing DME on DMI and BW (R² = 0.45). Animals were ranked into three groups namely high RME (>0.5 SD above the mean), medium RME (±0.5 SD above/below the mean), and low RME (>0.5 SD below the mean). Low RME animals produced 17.6% and 30.4% less (P < 0.05) DME compared with medium and high RME animals, respectively. A ~30% reduction in MY and MI was detected in low versus high RME animals. Positive correlations were apparent among all methane traits with RME most highly associated with (r = 0.86) DME. MY and MI were correlated (P < 0.05) with DMI, growth, feed efficiency, and carcass output. High RME had lower (P < 0.05) ruminal propionate compared with low RME animals and increased (P < 0.05) butyrate compared with medium and low RME animals. Propionate was negatively associated (P < 0.05) with all methane traits. Greater acetate:propionate ratio was associated with higher RME (r = 0.18; P < 0.05). Under the ad libitum feeding regime deployed here, RME was the best predictor of DME and only methane trait independent of animal productivity. Ranking animals on RME presents the opportunity to exploit interanimal variation in enteric emissions as well as providing a more equitable index of the methanogenic potential of an animal on which to investigate the underlying biological regulatory mechanisms.     

饲料中添加紫花苜蓿鲜草对肉牛生长性能及养分表观消化率的影响

为研究紫花苜蓿鲜草对肉牛生长性能及养分表观消化率的影响,采用单因素设计试验,选择体重相近的肉牛90头,随机分成3组,每组3个重复,每个重复10头。1组为空白对照组饲喂基础日粮,2、3组分别在风干物质的基础上添加5%、10%的紫花苜蓿鲜草,预试验10 d,试验期为60 d,在试验期间测定肉牛生长性能和养分表观消化率。结果表明:(1)试验3组的试验末重、平均日增重分别较对照组提高3.30%、14.77%(P <0.05),试验2组和3组的平均日采食量均高于1组(P> 0.05),试验3组的料重比分别较对照组降低7.20%(P <0.05);(2)试验2、3组的粗脂肪、粗灰分、钙、磷的表观消化率均高于1组(P> 0.05);试验3组粗蛋白质、中性洗涤纤维、酸性洗涤纤维表观消化率分别较对照组提高13.85%、18.83%、21.03%(P <0.05)。结论,10%紫花苜蓿鲜草可以提高肉牛的生长性能和养分表观消化率。     

肉牛常见饲料干物质和蛋白质瘤胃降解特性和小肠消化率研究

[方法]选用装有瘤胃瘘管和小肠瘘管的肉牛作为试验动物,尼龙袋法测定肉牛常见饲料干物质(DM)和粗蛋白(CP)的瘤胃降解特性和小肠消化率。[结果]结果表明,DM瘤胃有效降解率由高到低为玉米粉、麦麸、苜蓿干草、豆粕、菜籽粕、玉米青贮、醋糟、白酒糟;CP瘤胃有效降解率由高到低为苜蓿干草、麦麸、豆粕、醋糟、玉米粉、玉米青贮、菜籽粕、白酒糟;DM小肠消化率由高到低为豆粕、菜籽粕、玉米粉、白酒糟、醋糟、麦麸、苜蓿干草、玉米青贮;CP小肠消化率由高到低为豆粕、菜籽粕、玉米粉、苜蓿干草、麦麸、白酒糟、玉米青贮、醋糟。[结论]试验表明,不同饲料瘤胃降解特性不同,为小肠提供过瘤胃可消化蛋白的能力不同,且饲料的DM小肠消化率小于CP小肠消化率。     

秸秆制粒对肉牛反刍、消化、瘤胃发酵及体增重的影响

本研究测定分析了秸秆制粒饲喂肉牛对其采食、反刍、养分表观消化率、瘤胃发酵和增重的影响,以丰富秸秆饲料化利用方式。试验选取30头18月龄左右、活重接近的西杂肉牛,随机分成3组(每组10头),分别饲喂粉碎玉米秸秆(对照组)、玉米秸秆颗粒饲料(试验Ⅰ组)及玉米秸秆精粗饲料颗粒(试验Ⅱ组)。结果表明,1)秸秆制粒饲喂肉牛,其采食、反刍、咀嚼时间均有所缩短,且每食团咀嚼时间显著少于对照组(P=0.004),而试验Ⅱ组采食时长显著低于对照组(P=0.032)。2)除试验Ⅰ组中性洗涤纤维的表观消化率显著低于对照组外(P<0.05),3组肉牛其他养分的表观消化率均无显著差异。3)秸秆粉碎制料后饲喂肉牛影响瘤胃发酵,与对照组比较,试验Ⅰ组瘤胃pH值及丁酸含量显著下降(P<0.05),而乙酸含量和乙酸/丙酸显著升高(P<0.05);试验Ⅱ组瘤胃液丁酸含量显著下降(P<0.05),乙酸/丙酸及NH₃-N含量显著升高(P<0.05)。4)秸秆粉碎制粒饲喂肉牛能显著增加日增重和饲料转化率(P<0.05),试验Ⅰ组及试验Ⅱ组日增重较对照组分别高出0.36和0.38 kg,饲料转化率(料重比)分别提高27.86%和29.09%。     

Effects of adding urea on fermentation quality of pruned persimmon branch silage and its digestibility,preference, nitrogen balance and rumen fermentation in beef cattle

Four cattle were used in a 4 × 4 Latin square design experiment to study digestibility, ruminal fermentation, nitrogen retention and preference of ensiling pruned persimmon branch (PPB) chips treated with urea. After 60 days of ensiling, urea‐treated PPB showed higher (P < 0.05) pH, acetic acid and ammonia‐N levels than no‐urea PPB. Both urea‐treated PPB and rice straw diets showed higher (P < 0.05) apparent digestibility and digestible nutrient content in cattle than no‐urea PPB diet. Neither mold nor yeast was detected in any urea‐treated PPB. Urinary and fecal excretion as well as nitrogen retention in cattle fed urea‐treated PPB were higher (P < 0.05) than in those fed no‐urea PPB and rice straw. With the exception that ruminal ammonia‐N levels in cattle fed urea‐treated PPB were higher (P < 0.05) than in those given no‐urea PPB and rice straw, ruminal pH, volatile fatty acid concentrations, and the acetic : propionic acid ratio of rumen content were unaffected by diets. The rank order of preference was rice straw > low‐urea > no‐urea > high‐urea. The results suggested that urea treatment of PPB inhibited growth of mold and yeast during silage storage, enhanced its digestibility and had nutritive value almost equivalent to that of rice straw.     

Effects of isovalerate on ruminal fermentation,urinary excretion of purine derivatives and digestibility in steers

The objective of this study was to evaluate the effects of isovalerate supplementation on rumen fermentation, urinary excretion of purine derivatives and feed digestibility in the total tract of steers. Eight ruminally cannulated Simmental steers were used in a replicated 4 × 4 Latin square experiment. The treatments were: control (without isovalerate), low isovalerate (LIV), medium isovalerate (MIV) and high isovalerate (HIV) dosage of isovalerate at 100, 200 and 300 mg isovalerate per kg dry matter (DM) intake respectively. Diets consisted of corn stover and concentrate (60/40, DM basis). Dry matter intake was approximately 9 kg per day that was 90% of ad libitum intake including 5.4 kg corn stover and 3.6 kg concentrate. Ruminal pH (6.72–6.54) was linearly (p < 0.03) reduced, whereas total volatile fatty acid concentration (64.6–74.7 mmol/l) was linearly (p < 0.01) and quadratically (p < 0.01) increased with increasing isovalerate supplementation. Ratio of acetate to propionate increased linearly (p < 0.01) from 2.78 to 3.39 as isovalerate supplementation increased because of the increase in acetate production and decrease in propionate production. In situ ruminal degradation of amylase‐treated neutral detergent fibre (aNDF) of corn stover was improved, but crude protein (CP) degradability of soybean meal decreased with increasing isovalerate supplementation. Urinary excretion of purine derivatives was quadratically (p < 0.01) changed by altering isovalerate supplementation (50.5, 54.3, 58.9 and 55.2 mmol/day for control, LIV, MIV and HIV, respectively). Similarly, digestibilities of organic matter, aNDF and CP in the total tract were linearly and quadratically increased with increasing isovalerate supplementation. The results of this study indicate that supplementation of diet with isovalerate improved ruminal fermentation and feed digestion in beef cattle. It was suggested that the isovalerate stimulated the digestive micro‐organisms or enzymes in a dose‐dependent manner.     

Combined effects of 3-nitrooxypropanol and canola oil supplementation on methane emissions,rumen fermentation and biohydrogenation,and total tract digestibility in beef cattle

The individual and combined effects of 3-nitrooxypropanol (3-NOP) and canola oil (OIL) supplementation on enteric methane (CH₄) and hydrogen (H₂) emissions, rumen fermentation and biohydrogenation, and total tract nutrient digestibility were investigated in beef cattle. Eight beef heifers (mean body weight ± SD, 732 ± 43 kg) with ruminal fistulas were used in a replicated 4 × 4 Latin square with a 2 (with and without 3-NOP) × 2 (with and without OIL) arrangement of treatments and 28-d periods (13 d adaption and 15 d measurements). The four treatments were: control (no 3-NOP, no OIL), 3-NOP (200 mg/kg dry matter [DM]), OIL (50 g/kg DM), and 3-NOP (200 mg/kg DM) plus OIL (50 g/kg DM). Animals were fed restrictively (7.6 kg DM/d) a basal diet of 900 g/kg DM barley silage and 100 g/kg DM supplement. 3-NOP and OIL decreased (P < 0.01) CH₄ yield (g/kg DM intake) by 31.6% and 27.4%, respectively, with no 3-NOP × OIL interaction (P = 0.85). Feeding 3-NOP plus OIL decreased CH₄ yield by 51% compared with control. There was a 3-NOP × OIL interaction (P = 0.02) for H₂ yield (g/kg DM intake); the increase in H₂ yield (P < 0.01) due to 3-NOP was less when it was combined with OIL. There were 3-NOP × OIL interactions for molar percentages of acetate and propionate (P < 0.01); individually, 3-NOP and OIL decreased acetate and increased propionate percentages with no further effect when supplemented together. 3-NOP slightly increased crude protein (P = 0.02) and starch (P = 0.01) digestibilities, while OIL decreased the digestibilities of DM (P < 0.01) and neutral detergent fiber (P < 0.01) with no interactions (P = 0.15 and 0.10, respectively). 3-NOP and OIL increased (P = 0.04 and P < 0.01, respectively) saturated fatty acid concentration in rumen fluid, with no interaction effect. Interactions for ruminal trans-monounsaturated fatty acids (t-MUFA) concentration and percentage were observed (P = 0.02 and P < 0.01); 3-NOP had no effect on t-MUFA concentration and percentage, while OIL increased the concentration (P < 0.01) and percentage (P < 0.01) of t-MUFA but to a lesser extent when combined with 3-NOP. In conclusion, the CH₄-mitigating effects of 3-NOP and OIL were independent and incremental. Supplementing ruminant diets with a combination of 3-NOP and OIL may help mitigate CH₄ emissions, but the decrease in total tract digestibility due to OIL may decrease animal performance and needs further investigation.     

Effects of cyclodextrin-iodopropane complex on methane production, ruminal fermentation and microbes, digestibility and blood metabolites in steers

The effects when adding cyclodextrin‐iodopropane complex (CD‐IP) to a diet, on ruminal fermentation and microbes, digestibility, blood metabolites and methane production, were evaluated using four Holstein steers in a cross‐over design. The steers were fed Sudangrass hay plus concentrate mixture at a ratio 1.5:1, and CD‐IP (1% of dry matter) was given twice daily by mixing with concentrate mixture. Rumen and blood samples were collected at 0, 2, and 5 h after morning dosing. Ruminal pH and numbers of protozoa were unaffected by CD‐IP treatment. Ruminal molar proportion of acetate was decreased (P < 0.05), and propionate was increased (P < 0.01) at 2 h after CD‐IP dosing. Proportion of butyrate was increased (P < 0.05) and ammonia‐N was decreased (P < 0.05) at 2 and 5 h after CD‐IP dosing. Adding CD‐IP had no effect on the feed intake and digestion of nutrients. Plasma glucose was increased and urea‐N was decreased (P < 0.05) at 2 and 5 h after CD‐IP dosing. Methane production was decreased (P < 0.05) by approximately 18% in the treatment steers. Numbers of methanogenic bacteria were decreased (P < 0.05), while total viable counts, cellulolytic, sulfate reducing and acetogenic bacteria were unaffected. The present results are the first to show that CD‐IP can partially inhibit in vivo ruminal methanogenesis without adverse effects on digestion of nutrients.     

胍基乙酸对锦江黄牛瘤胃体外发酵参数的影响

为研究饲料中添加胍基乙酸对牛瘤胃体外发酵参数的影响,试验选取3只身体健康、2岁左右、体重为(200~250)kg、安装瘤胃瘘管的锦江黄牛供采集瘤胃液。采取体外产气法对添加不同水平胍基乙酸(0.1%、0.2%、0.3%、0.4%)体外发酵培养,测定24 h培养液中pH、氨态氮(NH3-N)、挥发性脂肪酸(VFA)、微生物蛋白(MCP)浓度及干物质消化率等瘤胃发酵指标。结果表明:(1)随着胍基乙酸添加量的增加,0.4%添加组产气量显著提高40.82%(P<0.05)。胍基乙酸添加组的pH显著低于空白对照组(P<0.05),但均在正常范围内;NH3-N浓度随着添加剂量的增加呈先降低后升高趋势,其中0.1%、0.2%添加组显著低于空白对照组(P<0.05),分别降低了10.55%、15.29%。瘤胃微生物蛋白含量随着胍基乙酸添加量的增加而增加,0.4%添加组显著提高了1.41%(P<0.05)。干物质消化率(IVDMD)随着胍基乙酸添加量的增加先增加后减少,其中0.4%添加组显著提高了11.24%(P<0.05)。(2)胍基乙酸组挥发性脂肪酸总量、乙酸、丙酸、丁酸有上升趋势,并且0.4%添加组显著高于空白对照组(P<0.05),其中TVFA提高了6.58%,丙酸含量提高了9.08%。但是乙酸/丙酸各组无显著差异(P>0.05)。综上所述,胍基乙酸添加可以促进瘤胃发酵功能。     

Effects of over-load iron on nutrient digestibility,haemato-biochemistry,rumen fermentation and bacterial communities in sheep

There is a risk of iron overload in grazing livestock. However, the effects on nutrient absorption and rumen function induced by excessive iron have not been well understood. Therefore, the purpose of present study was to investigate the impact of over-load iron on growth performance, nutrient digestibility, blood biochemistry, rumen fermentation and bacterial communities in sheep. Twenty-four German Mutton Merino cross-bred sheep with weight (42.66 ± 2.34 kg BW) were randomly divided into 4 groups, each with 6 replicates and 1 sheep per replicate. The basal diet consisted of 60% Leymus chinensis hay and 40% concentrate. The sheep in 4 groups were fed the basal diets supplemented with 50 (Control), 500 (T1), 1,000 (T2) and 1,500 (T3) mg Fe/kg as ferrous sulphate monohydrate (FeSO₄·H₂O) respectively. And the actual contents of iron in the diet were determined to be 457.68 (control), 816.42 (T1), 1,256.78 (T2) and 1,725.63 (T3) mg/kg respectively. The experiment lasted 62 days including a 7-day metabolism trial. During the whole experiment, the digestibility of dry matter, organic matter, neutral detergent fibre and acid detergent fibre showed a quadratic increase with increasing over-load iron levels (p < .05), and maximum responses were found with 500 mg/kg supplementation. However, the response of total VFA concentration showed a quadratic decrease, as did the concentrations of propionate, butyrate and valerate (p < .05). Serum total iron-binding capacity on day 30 showed a quadratic decrease with the increase in high-dose iron, while the serum iron content increased linearly at day 60 (p < .05). Excessive iron resulted in the change in bacterial communities. An increase in over-load iron linearly decreased the abundance of bacteria in the phylum Bacteroidetes (p < .05), but linearly increased the Firmicutes (p = .037) and Proteobacteria (p = .018). In addition, there was a quadratic effect (p = .003) on the Fibrobacteres, which was higher in the 500 and 1,000 mg/kg Fe-supplemented groups. At the genus level, there were quadratic effects on the abundances of Selenomonas_1 (p = .023) and Ruminococcaceae_UCG-014 (p = .016). Furthermore, feeding of iron linearly increased the relative abundances of Succiniclasticum and Succinivibrionaceae_UCG-002 (p < .05). These results indicate that increasing ferrous sulphate monohydrate in diets had no negative impact on the growth performance, but it changed nutrient digestibility, blood iron parameters, rumen fermentation and bacterial communities in sheep.     

体外法研究延胡索酸二钠对瘤胃微生物发酵活力及甲烷产量的影响

为探讨延胡索酸二钠对瘤胃甲烷产量及瘤胃微生物发酵活力的影响,本研究共设计了3个试验来阐明该问题。试验1采用体外批次培养,研究了不同日粮条件下(高牧草日粮、中等水平牧草的日粮和低牧草日粮)添加延胡索酸二钠(0,4和7mmol/L)对山羊瘤胃微生物发酵及甲烷产量的影响。结果表明,较对照相比,添加延胡索酸二钠显著提高了累积产气量、pH值和TVFA产量(P<0.05),降低了甲烷产量(P<0.05),其中高牧草日粮组下降幅度最大。试验2探讨了延胡索酸二钠对黄化瘤胃球菌发酵粗饲料活力的影响。结果表明,与对照组相比;添加延胡索酸二钠显著提高了黄化瘤胃球菌数量及其对黑麦草的降解率(P<0.05);试验3探讨了延胡索酸二钠对瘤胃真菌发酵粗饲料活力的影响,结果显示,延胡索酸二钠显著降低了厌氧真菌发酵的总产气量、干物质消失率及羧甲基纤维素酶酶活(P<0.05)。结果说明,延胡索酸二钠在降低甲烷产量方面与发酵底物的天然特性有关,其中对高牧草日粮的作用效应最为显著;延胡索酸二钠可提高瘤胃混合微生物与瘤胃纤维降解菌发酵粗饲料的能力,但对瘤胃真菌的发酵活力具有抑制效应。     

Effects of blend of canola oil and palm oil on nutrient intake and digestibility,growth performance,rumen fermentation and fatty acids in goats

The study examined the effects of blend of 80% canola oil and 20% palm oil (BCPO) on nutrient intake and digestibility, growth performance, rumen fermentation and fatty acids (FA) in goats. Twenty‐four Boer bucks were randomly assigned to diets containing 0, 4 and 8% BCPO on a dry matter basis, fed for 100 days and slaughtered. Diet did not affect feed efficiency, growth performance, intake and digestibility of all nutrients except ether extract. Intakes and digestibilities of ether extract, unsaturated fatty acids (FA) and total FA were higher (P < 0.05) while digestibility of C18:0 was lower (P < 0.05) in oil‐fed goats than the control goats. Total volatile FA, acetate, butyrate, acetate/propionate ratio and methane decreased (P < 0.05) with increasing BCPO but propionate, NH₃‐N and rumen pH did not differ between diets. Ruminal concentration of C18:0, n‐3 FA and total FA increased (P < 0.05) while C12:0, C14:0, C15:0 and n‐6 FA decreased with increasing BCPO. Analysis of the FA composition of Triceps brachii muscle showed that concentrations of C16:0, C14:0 and C18:2n‐6 were lower (P < 0.05) while C18:1n‐9, C18:3n‐3 and C20:5n‐3 were higher in oil‐fed goats compared with control goats. Dietary BCPO altered muscle lipids without having detrimental effects on nutrient intake and digestibility and growth performance in goats.