低磷饲料中补充柠檬酸对大口黑鲈生长和营养物质利用率的影响

为了探究饲料中添加柠檬酸对大口黑鲈（Micropterus salmoides）生长、营养物质利用和氮（N）、磷（P）排放的影响,分别配制磷酸二氢钙（MCP）添加量为5、10（低磷饲料）、15 g/kg （对照饲料）的3组饲料（P5,P10,P15）,在低磷饲料P5和P10中分别添加10 g/kg的柠檬酸,共5组实验饲料。投喂初始体质量为（16.0±0.16） g的大口黑鲈60 d。结果显示,随着MCP添加量的增加,大口黑鲈增重率、全鱼磷含量、粗蛋白沉积率、磷消化率、椎骨磷和血浆磷含量均显著增加（P<0.05）,N排放量和全鱼粗脂肪含量显著下降（P<0.05）,且均在P15组达到最佳水平。在P5饲料中添加柠檬酸,显著提高了鱼体增重率（+5.6%）和血浆磷含量,降低了饲料系数（-0.05）和N排放量（P<0.05）,达到了和P10组基本一致的水平（P>0.05）;在P10饲料中添加柠檬酸,在数值上改善了生长性能（P>0.05）,达到了和P15组基本一致的水平（P>0.05）。此外,在P5和P10饲料中补充柠檬酸,均显著提高了磷消化率,降低了P排放量（P<0.05）。综上所述,在低磷饲料中添加10 g/kg的柠檬酸可改善大口黑鲈生长、提高饲料和磷的利用率。     

The Effect of Yucca schidigera Extract on Ruminal Fermentation and Parameters Traits in Sheep

In a completely randomized block design experiment, 16 ruminally cannulated sheep (40 ± 2.1 kg)fed a 50% concentrate 50% forage diet (DM basis) were given intraruminal doses of powdered Yucca schidigera extract (YSE). Doses of 0 (control), 100, 200, or 300 mg kg-1 diet were given at 8 p.m. and 4 a.m. On 15, 16, and 17 d of the experimental period, ruminal contents were sampled 0, 2, 4, 6, and 8 h after dosing, and blood samples were collected at the end of the experiment (18th and 19th d). Acidity was not affected (P＞0.05) by the addition of YSE. Compared with the control, ruminal propionate concentration was increased by 29.4 and 29.8% (P＞0.05) and the acetic acid concentration was decreased by 15.1 and 19.8% (P＞0.05) at 4 and 6 h after YSE (300 mg kg-1) dosing, respectively. Ruminal ammonia concentration in the first 2 h after feeding was higher (P＜0.05) in the sheep that did not receive YSE (increased by 17.57 mg 100 mL-1) than in those that received 200 mg kg-1 (increased by 6.77 mg 100 mL-1) or 300 mg kg-1 (increased by 6.50 mg 100 mL-1) YSE. Protozoan populations in the rumen were lower (P ＜ 0.05) in the animals that received 300 mg kg-1 of YSE compared with the control. All serum parameters of the four groups were in the normal range and were similar among the treatment groups (P＞0.05), after being fed for 19 d with different doses of YSE. The effect of YSE on ruminal ammonia concentration likely resulted from a decreased concentration of protozoan populations and, presumably, from ammonia binding by YSE.     

柠檬酸在早期断奶仔猪日粮中的应用

将４８头早期断奶仔猪分为３组,其中两个试验组分别加入柠檬酸０．７％（１组）和１．０％（２组）,另一组不加为空白对照。３周试验结果表明,日增重１组和２组分别比对照组提高１２．１８％和２．２４％,组间差异不显著（Ｐ＞０．０５）。饲料利用率１组和２组分别比对照组提高５．５６％和１５．６９％。头均全期经济效益１组和２组比对照组提高１２．７７％和６．３２％,１组又比２组提高６．０６％。     

Effect of oilseeds rich in linoleic and linolenic acids on milk production and milk fatty acid composition in dairy cows

Nine multiparous cows averaging 93±13 days in milk production (DIM) were used in a triple 3×3 Latin square design to determine the effects of feeding them whole roasted flaxseed, cracked roasted soybean and fresh alfalfa in the diet on milk production, milk fatty acid profiles and the digestibility of nutrients. Each experimental period lasted 30 d and a sample collection was performed during the last 7 d. The cows were fed on the control basal diet (CON) or diets containing whole roasted flaxseed (FLA) or cracked roasted soybean (SOY). All diets were fed as a total mixed ration (TMR) and had similar concentrations of crude protein (CP), Net Energy Lactation (NEL), acid detergent fibre (ADF) and neutral detergent fibre (NDF). The dry matter intake (DMI) was not significantly different (P>0.05), but tended to increase in FLA and SOY diets compared with the control (P>0.05). Cows in all treatments had a similar milk yield, although 4% fat corrected milk (FCM) yield was higher on the FLA and SOY diets than on the CON diet. Milk fat percentage (3.45%) increased in the FLA diet compared with the control (3.31%) and SOY diets (3.39%). Milk protein percentages were similar among the diets (P>0.05). There were similar digestibilities of DM, CP and ADF among the treatments and lower digestibilities of NDF and ether extract in the SOY diet compared with the CON diet. Feeding various oilseeds significantly increased the concentrations of C_18:1, C_18:3 and conjugated linoleic acid (CLA). The FLA diet decreased the ratio of omega-6 to omega-3 fatty-acids in the milk, which would improve the nutritive value of the milk.     

植酸酶和益生素对青年蛋鸡生长性能的影响

将510只45日龄罗曼褐壳蛋鸡随机分为5个处理,每处理6个重复,每重复17只。设计5种饲粮:(1)正对照组;(2)负对照组(营养水平降低10%,钙和总磷除外);(3)负对照组+0.02%植酸酶(降低总磷和有效磷0.05%);(4)负对照组+0.15%益生素;(5)正对照组+0.02%植酸酶(降低总磷和有效磷0.10%)。结果表明:(1)负对照组蛋鸡生长速度与正对照组相当,但粪中干物质(P<0.05)和钙含量(P<0.01)显著提高;(2)负对照组添加植酸酶后,鸡粪磷排泄量极显著减少(P<0.01);与正对照组相比,采食量增加(P<0.01),鸡粪钙含量提高(P<0.05);(3)添加益生素后,蛋鸡采食量增加(P<0.01),其余所观测指标不受影响(P>0.05);(4)正、负对照组饲粮添加植酸酶后,磷表观代谢率分别提高30.06%(P=0.09)和29.05%(P>0.05);(5)高麸皮饲粮组(处理2和3)与低麸皮饲粮组(处理1和5)鸡生长性能相当。     

日粮粗蛋白质水平及添加尿素对肉鸡生产性能的影响

将288羽21日龄艾维茵肉鸡分为6组,设计16%,18%和20%粗蛋白质(CP)不同水平,及其分别添加1g/kg尿素(U)共构成6组日粮,随机分配给6组肉鸡,观测不同处理对肉鸡生产性能及血液生化指标的影响。结果表明:(1)随日粮CP水平提高,肉鸡采食量下降,16%CP及16%CP+U组显著高于其他组(P<0.05);全期平均日增重以16%CP+U及18%CP组最高(P<0.05);全期料肉比以16%CP和18%CP+U组最高(P<0.05)。(2)随日粮CP水平提高,肉鸡腹脂率下降,20%CP及20%CP+U组显著低于其他组(P<0.05);胸肉率18%CP组显著高于16%CP,16%CP+U及20%CP+U组(P<0.05);添加尿素腹脂率趋于降低(P>0.05);20%CP+U组胸肉率显著降低(P<0.05)。(3)CP水平及添加尿素显著影响血清尿素氮(BUN)及血清总蛋白(BTP)。说明在本试验能量水平及氨基酸模式下,低蛋白质日粮(16%)加1g/kg尿素可使肉鸡获得较好的生产性能。     

低蛋白日粮不同磷水平及添加植酸酶对生长猪生产性能及部分血清生化指标的影响

选择90头平均体重30 kg左右的杜长大三元杂交猪,随机分为3处理,每个处理5个重复,每个重复6头猪,通过分别饲喂3种日粮:(1)0.30%有效磷高磷组日粮;(2)0.24%有效磷对照组日粮;(3)0.15%有效磷低磷+植酸酶组日粮,来研究在低蛋白日粮中不同磷水平及添加植酸酶对生长猪生产性能血清生化指标的影响。结果表明:各组间的生产性能无显著差异(P>0.05);0.15%+酶低磷组与0.24%对照组相比生产性能相当(P>0.05)。随日粮磷水平升高血清钙浓度有下降的趋势(P>0.05)、血清磷浓度显著升高(P<0.05)、血清碱性磷酸酶活性显著提高(P<0.05),低磷加酶日粮组血清磷酸酶活性最高。     

不同处理下蛋青鸡血浆游离Leu比放射性活度的变化

在绝食、强饲无氮日粮(NFD)、CP20%(豆粕组)、CP20%(棉粕组)4种处理下,给蛋青鸡每公斤体重静脉一次注射1110MBq[3H]Leu,分别于注射后5min,30min,4h,24h,36h,48h翅静脉采血,测定各时间点去蛋白血浆游离Leu浓度和比放射性活度。结果表明,去蛋白血浆中游离Leu浓度绝食组和NFD组显著低于豆粕组和棉粕组(P<0.05);血浆游离Leu的比放射性活度(SRp),以NFD组与绝食组相近,且较高,棉粕组最低,但4种处理间无显著差异(P>0.05)。血浆游离Leu比放射性活度呈显著的指数衰变规律(P<0.05)。     

Performance and Nutrient Utilization of Layers Fed Diet Supplemented with Microbial Phytase and Cellulase

1　Introduction　　The majority of the P in cereal grains and oilseed meals is organically bound as phytic acid orphytate.Phytate has potential to form insoluble complexes with protein and minerals such as P and Ca ,Cu ,Fe ,Mn ,Zn 〔1,2〕,which can negatively affect availabilities and digestibilities of minerals,protein or aminoacids〔3 ,4〕.Furthermore,phytate is also able to bind endogenous proteases such as trypsin and chymotrypsinin the gastrointestinal tract〔5〕,and these complexes ma…     

不同无机磷水平日粮中添加植酸酶对肉鸡生长性能及养分利用率的影响

研究了不同无机磷水平日粮中添加植酸酶对肉鸡生长性能、蛋白质及矿物质元素利用率的影响.选取1日龄肉鸡1 500只,随机均分为5组,对照组以磷酸氢钙为磷源,其余为试验组,其磷酸氢钙水平分别为对照组的75%、50%、25%和0%,并添加植酸酶,各组钙磷比值在1.2～1.4之间.结果表明:无磷酸氢钙组日均采食量、日增重均显著低于对照组(P<0.05),50%磷酸氢钙组日增重最高,料重比最低.各处理组的净蛋白利用率均高于对照组,但差异不显著(P>0.05).矿物质元素利用率随无机磷含量减少呈升高趋势.随无机磷水平降低,各试验组排泄物中磷含量分别比对照组依次降低了11.0%、17.9%、23.9%、28.4%.综合生长性能及养分利用率以50%磷酸氢钙添加植酸酶组(0～4周:钙0.76%,总磷0.54%;5～7周:钙0.70%,总磷0.53%)效果较好.     

蛹虫草真菌发酵五味子药渣对仔猪生长性能、 饲料消化率和血清生化指标的影响

研究蛹虫草真菌发酵五味子药渣菌质对仔猪生长性能、饲料消化率和血清生化指标的影响。选取28日龄断奶仔猪36头随机分为3组(每组3个重复,每个重复4头):空白对照组饲喂基础饲粮,阳性对照组基础饲粮中添加5 g·kg~(-1)的五味子,试验组基础饲粮中添加5 g·kg~(-1)的蛹虫草真菌发酵五味子药渣菌质。试验期21 d。结果表明,与空白对照组相比,试验组和阳性对照组仔猪料肉比和腹泻指数显著降低(P0.01或P0.05);粗蛋白质(CP)、粗脂肪(EE)、粗纤维(CF)和粗灰分(Ash)消化率提高;谷草转氨酶(AST)活性显著降低(P0.05),碱性磷酸酶(ALP)活性、总蛋白(TP)和白蛋白(ALB)含量均显著增加(P0.01或P0.05)。试验组尿素氮(BUN)显著降低(P0.05),但各组白球比(A/G)和谷丙转氨酶(ALT)活性差异不明显。试验组各检测指标变化趋势和阳性对照组一致。上述结果表明,在断奶仔猪基础饲粮中添加5 g·kg~(-1)的蛹虫草真菌发酵五味子药渣能显著改善断奶仔猪生长性能、主要营养物质消化率及血清生化指标。     

尿素、柠檬酸对雏鸡生长发育及血液生化指标的影响

 选择1日龄尼克红蛋公雏264只,随机分为6组,每组4个重复,每个重复11只,试验期42 d. 各组添加0％,0.1％尿素、0.2％尿素、0.4％尿素、0.3％柠檬酸、0.2％尿素＋0.3％柠檬酸,研究尿素、柠檬酸及其复合物对雏鸡生长发育及血液生化指标的影响。试验结果显示:（1）添加0.1％尿素显著提高雏鸡期末体重（P＜0.05）,并趋于改善日增重、全期采食量及饲料转化率(P＞0.05)。(2)与添加0.1％尿素相比,添加0.4％尿素显著降低期末体重、日增重、采食量(P＜0.05),并趋于降低饲料转化率(P＞0.05)。(3)添加0.4％尿素,显著提高血清尿素氮含量(P＜0.05),显著降低血清总蛋白含量(P＜0.05)。添加0.2％尿素＋0.3％柠檬酸复合物显著提高血清尿素氮含量(P＜0.05),但不影响血清总蛋白含量(P＞0.05)。添加0.1％和0.2％尿素,对血清尿素氮无影响(P＞0.05),而血清总蛋白显著降低(P＜0.05)。结果表明:饲料中添加0.1％尿素对雏鸡生长具有一定的调控作用。     

饲料中脂肪水平对海湾扇贝性腺发育、脂肪酸组成和组织结构的影响

为了探讨配合饲料及其脂肪含量对海湾扇贝性腺发育、脂肪酸组成和组织结构的影响,在基础饲料中通过梯度添加鱼油（质量分数为0%、3%、6%和9%）配置4种脂肪质量分数为7%、10%、14%和17%的等氮饲料（质量分数为47%粗蛋白）,分别记为F7、F10、F14和F17,并以小新月菱形藻（Nitzschia closterium f. minutissima）作为对照组,试验在室内1 000 L的水槽中进行,每种饲料随机投喂3组扇贝[初始体质量为（40.79±1.70） g],每个重复30只,试验周期30 d。结果显示：饲料中脂肪含量未显著影响扇贝死亡率（P>0.05）,对照组死亡率显著低于各个饲料处理组（P<0.05）。性腺指数（gonadosomatic index,GSI）随着饲料脂肪含量增加呈先上升后下降的趋势,在F14组GSI达到最高,与对照组差异不显著（P>0.05）,显著高于初始时期（P<0.05）。性腺中雌性部分含水量F10组最高,显著高于F17组（P<0.05）;雄性部分各处理组间差异不显著（P>0.05）。性腺中雌性部分粗脂肪含量显著高于雄性部分（P<0.05）。性腺中脂肪酸的含量PUFA>MUFA>SFA,饲料中脂肪含量显著影响性腺中SFA、MUFA、n-3PUFA、DHA和EPA的含量（P<0.05）,当饲料中脂肪含量为14%或17%时达到最高值。性腺组织切片可见,各个处理组卵母细胞和精原细胞充满整个滤泡腔,滤泡密集,滤泡之间无空隙。由此可得出,配合饲料替代部分单胞藻饲喂海湾扇贝,可使其性腺发育至育苗要求,饲料中脂肪质量分数为14%时可以代替部分单胞藻饲喂海湾扇贝促进性腺发育。     

Effect of Hypoglycemia on Performances, Metabolites, and Hormones in Periparturient Dairy Cows

In this research work, 24 multiparous holstein cows were used to evaluate the effect of hypoglycemia on periparturient metabolism and lactation performance. The cows were arranged into two groups of hypoglycemia （L） and normal plasma glucose （N） based on plasma glucose level. The same diets were fed ad libitum from 28 days before expected calving date to 28 days after calving. The parameters relative to energy balance, such as dry matter intake （DMI）, body weight （BW）, milk yield （MY）, and concentrations of plasma glucose, nonesterified fatty acids （NEFA）, β-hydroxybutyric acid （BHBA）, insulin （INS）, glucagons （GLN）, leptin （LP）, neuropeptide Y （NPY） in plasma were measured at regular intervals. Incidence of hypoglycemia was higher prepartum than that of postpartum （88% vs. 50%）, and the recurrence of hypoglycemia was reversed （31% vs. 100%）. Hypoglycemia did not affect feed intake before and after calving. With the increase of postpartum feed intake, incidence of hypoglycemia decreased rapidly, even disappeared at 28 days of postpartum. Hypoglycemia had no impact on prepartum BW, but BW in L group was lower than that of cows in N group at 1 day and 14 days of postpartum （P〈0.05）. Milk yield was not affected by hypoglycemia. Cows in L group had higher plasma NEFA concentration than cows in N group. It reached a peak （1442 μmol L^-1 vs. 1052 μmol L^-1） at day 1 of postpartum （P〈0.05）. Plasma BHBA concentration of cows in L group was higher than that in N group, which reached a peak （2.01 mmol L^-1 vs. 1.34 mmol L^-1） at 14 days of postpartum （P〈0.05）. Plasma concentration of INS and GLN was unaffected by treatment, but postpartum plasma GLN concentration obviously increased, especially in L group. Plasma concentration of LP and NPY before calving was unaffected by treatment, but postpartum LP level in L group was slightly lower than that in N group, and NPY level in L group was significantly higher than that in N group （P〈0.05）. Overall, periparturient dairy cows are easy to develop hypoglycemia, which stimulates lipid metabolism. Adaptive changes of some metabolites and hormones, such as NEFA, BHBA, INS, GLN, LP, NPY are of benefit to increase feed intake and recovery of NEB in periparturient period, but there still are some issues on interaction of those endocrine factors in the energy balance of periparturient cows to be understood further.     

不同磷酸二氢钙含量饲料中添加植酸酶对建鲤生长、磷利用、体组成和消化酶活性的影响

以初始体重为(12.8±0.2)g的建鲤(Cyprinus carpio var.Jian)为研究对象,探讨了在不同磷酸二氢钙含量饲料中添加包被酸性植酸酶对建鲤生长性能、磷利用率、体组成和肠消化酶活性的影响。共设5组饲料,即磷酸二氢钙含量分别为2.5%、2.0%、1.6%的3组饲料,及在2.0%、1.6%磷酸二氢钙饲料中添加2 000U/kg植酸酶的两组饲料。90 d的养殖实验结果表明:2.5%磷酸二氢钙组具有最高鱼体增重率,最低饲料系数和最低全鱼脂肪含量;1.6%磷酸二氢钙组的生长性能最低,全鱼脂肪含量最高;在2.0%磷酸二氢钙饲料中添加植酸酶,对生长、磷储积率和全鱼组成均没有显著影响,但提高了磷表观消化率和肠脂肪酶活性;在1.6%磷酸二氢钙饲料中添加植酸酶显著提高了鱼体增重率、磷表观消化率、磷储积率和全鱼粗蛋白、灰分含量(P0.05),降低了饲料系数和全鱼粗脂肪含量(P0.05),但对肠消化酶活性没有显著影响。上述结果表明:在含1.6%磷酸二氢钙饲料中添加包被酸性植酸酶可促进建鲤生长,降低鱼体粗脂肪含量,提高磷表观消化率和磷储积率。     

Response of lactating cows to supplemental rumen protected methionine and Niacin

Eight Chinese Holstein cows were used in a 4 × 4 Latin square design to determine the effects of rumen protected methionine (RPMet) and Niacin on milk yield and milk composition of lactating cows with 14 d adaptation and 6-d sampling periods. The cows were fed the control diet or the control diet plus RPMet (25 g·⁻¹), niacin (6 g·⁻¹), or RPMet (25 g·⁻¹) + niacin (6 g·⁻¹). The results showed that RPMet supplementation in the diet increased 4% fat corrected milk (FCM) yield (P < 0.05) and milk fat percentage (P < 0.05). However, supplemental RPMet had no effect on the solid non fat (SNF) (P > 0.05) and lactose percentage (P > 0.05). Dietary niacin supplementation increased milk yield (P < 0.05), milk protein percentage (P < 0.05) and lactose percentage (P < 0.05), but had no effect on milk fat percentage (P > 0.05) and SNF (P > 0.05). RPMet supplementation in the diet of lactating cows significantly decreased serum urea nitrogen (P < 0.01) and glucose contents (P < 0.05), but had no effects on nonesterified fatty acids (NEFA), total cholesterol and triglyceride (P > 0.05). Niacin supplementation influenced the contents of glucose and NEFA in serum, but had no effects on the urea nitrogen, total cholesterol and triglyceride (P > 0.05).     

植酸酶对肉鸭饲用原料钙与磷及其养分真利用率的影响

在18种常用肉鸭饲料原料中添加750 U/kg的植酸酶,通过鸭的强饲代谢试验来探究植酸酶对钙、磷及干物质、粗蛋白、粗脂肪、能量等真利用率的改善程度。结果表明:与加酶前比较,加酶后供试原料的总磷真利用率的提高幅度为0.92%~17.29%,其中,对次粉2、麦麸、米糠、玉米总磷的提高幅度差异达到显著或极显著水平,分别为11.79%(P0.05)、8.46%(P0.05)、17.29%(P0.05)、16.33%(P0.01),其余原料的总磷真利用率均有不同程度的提高,但差异不显著(P0.05);对钙真利用率的提高幅度为2.74%~22.12%,其中,对碎米(早)、玉米皮、小麦、麦麸、棉粕的钙真利用率的提高作用显著(P0.05),分别为16.37%、17.12%、30.75%、21.40%、22.12%,对糙米(晚)的提高幅度最小,仅为2.74%,对其余原料的提高幅度均在5%以上;加酶后供试原料的干物质、粗蛋白、粗脂肪、能量真利用率的提高幅度分别为0.03%~14.60%,0.71%~27.05%,2.00%~37.69%、0.17%~10.07%;植酸酶对原料有效磷的改进值范围为0.02~2.60 g/kg。综合分析,在肉鸭饲料原料中添加750 U/kg的植酸酶,对钙、磷及干物质、粗蛋白、粗脂肪真利用率的改善效果较明显。     

21～42日龄肉鸡能量和蛋白质需要量的研究

以商品代艾维茵肉鸡为供试动物,设置3个日粮代谢能(ME)水平,分别为12.55、12.97和13.38 MJ/kg;4个粗蛋白(CP)水平,分别为18.5%、19.0%、19.5%和20.0%.采用3×4因子设计进行饲养试验, 研究日粮ME和CP水平对22～42日龄肉鸡生产性能、胴体性能以及肉品质的影响.结果表明:(1)日粮ME水平对22～42日龄肉鸡的日均采食量、平均日增体质量、料重比和21日体质量影响极显著(P<0.01);日粮CP水平对22～42日龄肉鸡的日均采食量影响不显著(P>0.05),但对平均日增体质量、42日体质量和料重比影响极显著(P<0.01).日粮ME和CP的互作对22～42日龄肉鸡料重比影响极显著(P<0.01);较高的日粮ME水平和CP水平可获得理想的生产性能;(2)日粮ME水平对22～42日龄肉鸡半净膛率、腿肌率和腹脂率影响极显著(P<0.01),对屠宰率影响显著(P<0.05),对全净膛率和胸肌率影响都不显著(P>0.05);日粮CP水平与22～42日龄肉鸡的胸肌率呈正相关,对其他胴体性能指标影响不显著(P>0.05);(3)随日粮ME水平增加,腿肌的红度(a*)先降低后增加,但对胸肌红度(a*)影响不显著(P>0.05);胸肌和腿肌的黄色度值(b*)都与日粮ME和CP水平呈正相关;日粮ME水平对胸肌的亮度(L*)影响不显著(P>0.05);(4)胸肌的PH值与日粮ME水平呈负相关,腿肌的pH值随日粮CP水平的升高呈先上升后下降趋势;腿肌的持水率与日粮ME水平呈正相关.通过本试验并结合生产实际认为: 22～42日龄肉鸡适宜的ME水平为12.97MJ/kg,CP水平为19.0%～20.0%之间.     

Effect of dioscorea opposite waste on growth performance,blood parameters,rumen fermentation and rumen bacterial community in weaned lambs

This study investigated the effects of dioscorea opposite waste (DOW) on the growth performance, blood parameters, rumen fermentation and rumen microbiota of weaned lambs. Sixty healthy weaned Small-Tailed Han lambs (male, (22.68±2.56) kg initially) were used as the experimental animals. Four levels of concentrate: 0 (control, CON), 10% (DOW1), 15% (DOW2) and 20% (DOW3), were replaced with DOW in the basal diet as experimental treatments. The results showed that lambs fed the DOW2 diet had a higher (P<0.05) dry matter intake (DMI) than the other groups. There was no significant difference (P>0.05) among DOW groups in average daily weight gain (ADG), and replacing concentrate with DOW linearly or quadratically increased (P<0.05) the ADG, while lambs fed the DOW2 diet showed greater (P<0.05) ADG than the CON group. The relative plasma concentration of growth hormone (GH), insulin like growth factor-1 (IGF-1) and insulin were affected by DOW, replacing concentrate with DOW linearly or quadratically (P<0.05) enhanced the plasma concentration of GH, IGF-1 and insulin, which was significantly higher (P<0.05) in the DOW2 group than in the CON, DOW1 and DOW3 groups. In addition, the DOW treatment showed a lower (P<0.05) concentration of blood urea nitrogen (BUN) than the CON group. Replacing concentrate with DOW quadratically decreased (P<0.05) the ruminal ammonia nitrogen (NH₃-N) and increased (P<0.05) the total of volatile fatty acids (TVFAs) at 0 and 4 h after feeding as well as linearly decreased (P<0.05) the NH₃-N at 8 h after feeding. Replacing concentrate with DOW linearly decreased (P<0.05) the propionate and increased the aceate before feeding, and linearly decreased (P<0.05) propionate and quadratically increased (P<0.05) the aceate at 4 and 8 h after feeding. Lambs fed the DOW2 diet increased the phylum Firmicutes and genera Succiniclasticum and Ruminococcus_1 groups, whereas decreased (P<0.05) the relative abundance of phylum Deferribacteres and genera intestinimonas and Ruminiclostridium. In summary, replacing the concentrate with 15% DOW was beneficial for improving the rumen fermentation and ADG by increasing the DMI and modulating the rumen microbial community.     

低鱼粉饲料中添加微囊氨基酸和蛋白酶对凡纳滨对虾生长、营养物质利用和消化酶活性的影响

试验旨在探究低鱼粉饲料中添加微囊氨基酸和蛋白酶对凡纳滨对虾(Litopenaeus vannamei)生长、营养物质利用、消化酶活性的影响。试验设计5组等氮等能饲料:鱼粉含量20%的正对照组、鱼粉含量15%的负对照组(豆粕等蛋白替代鱼粉)、在负对照饲料中分别添加微囊赖氨酸(500 mg/kg)、蛋氨酸(900 mg/kg)(达到正对照饲料一致水平),175 mg/kg蛋白酶,微囊赖氨酸、蛋氨酸和175 mg/kg蛋白酶,饲喂初始体质量为(2.96±0.02)g的凡纳滨对虾6周。结果表明:正对照组具有最大增重率和最低饲料系数,而负对照组的增重率最低,饲料系数最高;在负对照饲料中补充氨基酸、蛋白酶后,有提高增重率和降低饲料系数趋势(P0.05);同时补充氨基酸和蛋白酶后,虾体增重率提高11.5%,饲料系数降低0.18(P0.05),显著提高了蛋白质沉积率、干物质和粗蛋白消化率。全虾水分、粗蛋白、粗脂肪、粗灰分含量,虾体粗脂肪沉积率和肝胰腺淀粉酶、脂肪酶活性在各组均无显著差异(P0.05)。以上结果表明,在含15%鱼粉的饲料中单独补充900 mg/kg微囊蛋氨酸、500 mg/kg微囊赖氨酸或175 mg/kg蛋白酶,对凡纳滨对虾生长的改善不显著,联合添加微囊氨基酸和蛋白酶可显著提高虾体生长性能和营养物质利用率。