低蛋白质补充氨基酸日粮对哺乳母猪繁殖性能、背膘厚和乳成分的影响

研究旨在探讨低蛋白质补充氨基酸日粮对哺乳母猪繁殖性能、背膘厚和乳成分的影响。选择35头胎次、体重和体况相近的哺乳母猪,采用单因子试验设计,随机分为3个处理,每处理分别为13、11、11头母猪。对照组使用常规日粮,粗蛋白质水平为17.7%,试验Ⅰ、Ⅱ组分别使用低蛋白质补充氨基酸日粮,粗蛋白质水平为15.7%、13.7%,其氨基酸水平与对照组相近,哺乳期21 d。结果表明：①与对照组相比,试验Ⅰ、Ⅱ组21日龄断奶全窝重、哺乳期母猪采食量、仔猪窝采食量及成活率均无显著差异（P>0.05）,随着日粮蛋白质水平的降低母猪的失重有所增加,但各处理间差异不显著（P>0.05）;②随着日粮蛋白质水平的降低,母猪背膘损失比例减少,但各处理间差异不显著（P>0.05）;③与对照组相比,试验Ⅱ组的乳品质较好,但无显著差异（P>0.05）。以上结果说明,通过补充氨基酸降低哺乳母猪日粮粗蛋白质水平（由17.7%降至15.7%、13.7%）,不会影响母猪及仔猪的生产性能,是节约蛋白质资源的有效措施。     

Effect of Low Crude Protein Diet Supplemented with Amino Acids on Reproductive Performance and Protein Metabolism in Pregnant Sows

In order to study the effect of low crude protein (CP) diet supplemented with amino acids on the reproductive performance and protein metabolism in pregnant sows, a single-factor experimental design was used and twenty-four pregnant sows were randomly divided into three treatments with 8 replicas each according to parity,due date and body weight of sows. The pregnant sows in control group were fed conventional feed with CP level of 14.5%, and the pigs in experimental groups Ⅰ and Ⅱ were fed 12.5% and 10.5% of CP diets supplemented with amino acids,respectively. All diets contain similar amino acid concentration. The experiment began at 20 days after breeding and finished after farrowing. The results showed that:① Low CP diets supplemented with amino acids had no significant effect on the reproductive performance of sows,including the total litter size,number of live litter size,weight at birth and backfat thickness of sows (P>0.05).② The serum urea nitrogen of sows in the control group had no significant difference with experimental group Ⅰ (P>0.05),while significantly higher than experimental group Ⅱ (P<0.05).And there was no significant difference between experimental group Ⅰ and Ⅱ (P>0.05). Serum glucose content also had a downward trend with the decrease of CP level,and that of the control group had no significant difference with experimental group Ⅰ (P>0.05),while significantly higher than experimental group Ⅱ (P<0.05).There was no significant difference between experimental group Ⅰ and Ⅱ (P>0.05). ③ Apparent digestibility of CP showed a trend of increase with the decrease of dietary CP levels. CP apparent digestibility of experimental group Ⅰ had no significant difference with control group (P>0.05),while that of experimental groupⅡ was significant higher than other two group (P<0.05).In conclusion,the low CP diet supplemented with amino acids had no significant effects on the reproductive performance and backfat thickness in pregnant sows.     

低粗蛋白质补充氨基酸日粮对妊娠母猪繁殖性能和蛋白质代谢的影响

选择胎次、预产期、体重相近的妊娠母猪24头,采用单因子试验设计,随机分为3个处理,每个处理设8个重复。对照组饲喂常规饲料,粗蛋白质（CP）水平为14.5%,试验组Ⅰ和Ⅱ为低CP补充氨基酸日粮,其CP水平分别为12.5%和10.5%。各处理氨基酸水平相同。试验期为从配种后20 d左右确定受孕后开始,直到产仔结束。试验结果表明：①与对照组相比,妊娠母猪采食低CP日粮,对其繁殖性能如总产仔数、活仔数、初生重及背膘厚无显著影响（P>0.05）。②对照组血清尿素氮的含量与试验组Ⅰ差异不显著（P>0.05）,而显著高于试验组Ⅱ（P<0.05）。试验组Ⅰ的血清尿素氮的含量与试验组Ⅱ差异显著（P<0.05）。血糖含量随CP水平的降低有下降的趋势,对照组血糖含量与试验组Ⅰ差异不显著（P>0.05）,而与试验组Ⅱ差异显著（P<0.05）;试验组Ⅰ和Ⅱ血糖含量差异不显著（P>0.05）。③饲料CP的表观消化率随着CP的降低有上升的趋势,试验组Ⅰ与对照组相比差异不显著（P>0.05）,而试验组Ⅱ显著高于试验组Ⅰ和对照组（P<0.05）。综上所述,妊娠母猪采食低CP补充氨基酸日粮,对其繁殖性能及背膘厚无显著影响。     

低粗蛋白质氨基酸平衡日粮对仔猪生长性能、血液指标、营养物质表观消化率和腹泻率的影响

为研究不同水平低粗蛋白质（CP）氨基酸平衡日粮对10~25 kg仔猪的生长性能、血液指标、营养物质表观养分消化率和腹泻率的影响,选取320头10 kg健康的"杜×长×大"三元杂交断奶仔猪,随机分为4个处理,每个处理4个重复,每个重复20头仔猪。对照组饲喂基础日粮,CP水平为20.1%,其他组饲喂低CP补充氨基酸日粮,CP水平分别为18.3%、14.9%、13.2%,除根据需要补充L-赖氨酸、DL-蛋氨酸、L-苏氨酸、L-色氨酸外,还补充L-缬氨酸、L-异亮氨酸、L-苯丙氨酸和L-组氨酸等,共计8种晶体氨基酸,各处理氨基酸水平均达到或超过NRC（1998）猪营养需要量标准,试验期24 d。结果显示：①20.1% CP组仔猪平均日增重（ADG）显著高于13.2% CP（P<0.05）;各组间料重比（F/G）、平均采食量（ADFI）差异均不显著（P>0.05）。②20.1% CP组仔猪血清尿素水平最高,13.2% CP最低,二者差异极显著（P<0.01）;各组间总蛋白（TP）、白蛋白（ALB）、球蛋白（GLB）、白蛋白/球蛋白、胰岛素、血糖、免疫球蛋白（IgA）、IgG、IgM水平均差异不显著（P>0.05）。③13.2% CP、14.9% CP组仔猪CP表观消化率极显著低于20.1% CP组（P<0.01）;其余指标差异均不显著（P>0.05）。④20.1% CP组仔猪腹泻率最高,13.2% CP组腹泻率最低,且差异显著（P<0.05）。综上所述,日粮CP水平降低至14.9%时对仔猪的生长性能无不良影响;血清尿素水平、CP表观消化率均极显著对于对照组（20.1% CP）,仔猪腹泻率大大降低。因此10~25 kg断奶仔猪氨基酸平衡日粮CP水平可降低至14.9%,不影响仔猪的生长性能。     

低蛋白质氨基酸平衡饲粮对哺乳母猪生产性能及氮利用的影响

本研究旨在探讨低蛋白质氨基酸平衡饲粮对哺乳母猪生产性能及氮利用的影响。选择24头胎次、体重和体况相近的长白×大白哺乳母猪,随机分为4组,每组6头,每头母猪哺育12头仔猪。各组母猪分别饲喂粗蛋白质(CP)18%、17%、16%、14%的饲粮(后3种为低CP氨基酸平衡饲粮),哺乳期21d。结果表明:CP14%饲粮使母猪体重损失显著增加(P<0.05);CP14%饲粮组仔猪断奶窝重和窝增重分别较其他试验组显著下降(P<0.05);CP17%、CP16%饲粮可显著提高母猪CP和有机物的消化率(P<0.05),CP17%、CP16%、CP14%饲粮可显著提高母猪粗脂肪的消化率(P<0.05);CP16%、CP14%饲粮组总氮摄入量、吸收氮、总氮排出量均显著低于其他试验组(P<0.05),CP18%饲粮组血清尿素氮显著高于其他试验组(P<0.05)。     

Mammary arteriovenous differences of glucose, insulin, prolactin and IGF-I in lactating sows under different protein intake levels

Mammary uptake of nutrients is dependent on their availability in the circulation but the role of hormones in that process is not known. Arteriovenous differences (AVD) of glucose and key hormones across the mammary glands were therefore determined in sows fed varying levels of protein. Sixteen lactating sows (four/dietary treatment) were fed a 7.8, 13.0, 18.2 or 23.5% crude protein (CP) isocaloric diet throughout lactation and their litters were standardized to 11 pigs within 48 h of birth. The anterior main mammary vein and a carotid artery were cannulated on day 4+/-1 of lactation and blood samples were collected every 30 min over 6h on days 10, 14, 18 and 22 of lactation to measure glucose, insulin, IGF-I, and prolactin (PRL) concentrations. Amino acid data from these sows were previously published and used here to determine residual correlations. Dietary treatments had no effect on any of the insulin or PRL variables measured (P>0.1) and, on day 18 only, IGF-I AVD was greater (P=0.05) for sows on the 23.5% compared to the 18.2% diet. On days 18 and 22, sows fed the 13% CP diet had greater arterial, venous and AVD glucose concentrations than sows fed other diets (P<0.05). Total arterial amino acid concentrations were correlated to arterial insulin (P<0.001) and PRL (P<0.05) concentrations, but not to those of IGF-I (P>0.1). Mammary AVD for total (P<0.001) and essential amino acids (P<0.05) were correlated to arterial concentrations of insulin, but not to those of IGF-I (P>0.1) or PRL (P>0.1). Mammary AVD of both total (P<0.01) and essential (P<0.05) amino acids were also correlated to mammary PRL AVD. In conclusion, dietary protein level did not affect mammary AVD and circulating lactogenic hormone concentrations. Yet, amino acid utilization by the sow mammary gland seems to be regulated via both circulating insulin concentrations and PRL binding to and uptake by porcine mammary cells.     

不同比例低蛋白氨基酸平衡日粮对断奶仔猪生长性能及氮平衡的影响

为了解不同比例低蛋白氨基酸平衡日粮对断奶仔猪生长性能及氮平衡的影响,试验将96头初始体重9.8 kg左右的杜×长×大断奶仔猪随机分成4个处理,每个处理分别饲喂含不同蛋白水平的玉米-豆粕型饲粮(20%CP、19%CP、18%CP和17%CP),通过补充合成氨基酸,使各处理组的氨基酸与要求相一致。正式试验期为28 d,测定断奶仔猪生长性能、氮平衡指标。结果表明,日粮蛋白水平降至18%时,不会影响断奶仔猪生长性能,且显著降低尿氮、粪氮和总氮排放量(P<0.01);但随着日粮蛋白水平进一步降至17%时,显著降低仔猪平均日增重(P<0.01),显著增加料重比(P<0.01);18%CP组与17%CP组总氮排放量、氮表观利用率、氮表观生物学效价差异不显著(P>0.05)。说明添加合成氨基酸满足断奶仔猪需要,将日粮蛋白水平降至18%,不仅不会影响仔猪生长性能,而且还会降低氮排放,减少环境污染。     

Effects of beet pulp supplementation on growth performance,fecal moisture,serum hormones and litter performance in lactating sows

This study was conducted to evaluate effects of beet pulp supplementation on growth performance, fecal moisture, serum hormones and litter performance in lactating sows. Ninety primiparous sows (Landrace × Yorkshire) were randomly allotted to one of three dietary treatments in a 21‐day trial starting 3 days before parturition. The three dietary treatments were supplemented with 0, 10 and 20% beet pulp, respectively. Backfat loss and fecal moisture content were increased (P < 0.05), where cortisol and norepinephrine levels were decreased (P < 0.05) in sows fed beet pulp supplementation diets compared with control diet, but there was no difference between 10% and 20% beet pulp supplementation treatments. No effect was observed on bodyweight, average daily intake, weaning to estrus interval, epinephrine level in sows and litter weight, litter size, survivability in piglets among dietary treatments. Taken together, beet pulp supplementation has no significant effect of growth performance of lactating sows and piglets with decreased cortisol and norepinephrine levels in lactating sows, but it can increase fecal moisture content which is beneficial for sow feces excretion.     

不同剂型酸化剂对哺乳母猪生产性能、初乳成分和肠道菌群结构的影响

本试验旨在比较2种不同剂型酸化剂对哺乳母猪生产性能、初乳成分和肠道菌群结构的影响。试验选择30头体况相近、预产期接近的2~4胎长大二元杂交母猪,随机分成3个组,每组10个重复,每个重复1头母猪。在试验期间各组母猪分别饲喂基础饲粮(对照组)、基础饲粮+0.3%吸附型酸化剂(A组)、基础饲粮+0.1%微囊型酸化剂(B组)。预试期7 d(母猪分娩前7天)、正试期26 d(从母猪分娩开始至泌乳结束)。结果表明:与对照组相比,A组和B组母猪的泌乳期平均日采食量分别提高4.9%(P0.05)和5.3%(P0.05),仔猪断奶均重分别提高2.6%(P0.05)和7.4%(P0.05)。A组和B组的母猪初乳中乳脂、乳蛋白、尿氮素、免疫球蛋白G和免疫球蛋白A含量均高于对照组(P0.05),而乳糖含量则低于对照组(P0.05)。与对照组相比,B组母猪饲粮蛋白质消化率显著提高(P0.05),且粪便中大肠杆菌数量显著降低(P0.05);A组母猪粪便中大肠杆菌数量显著降低(P0.05)。由此可见,微囊型酸化剂在提高仔猪断奶重以及哺乳母猪饲粮蛋白质消化率和改善肠道菌群结构方面有一定功效,而吸附型酸化剂在改善哺乳母猪肠道菌群结构方面有一定功效。     

Effect of dietary L-carnitine supplementation on growth performance of piglets from control sows or sows treated with L-carnitine during pregnancy and lactation

Previous studies showed that supplementation of sows' diets with L-carnitine increases body weights of their piglets at birth. This study was performed to investigate whether piglets of sows treated with L-carnitine differ in their growth potential from that of piglets of untreated control sows after weaning. It was also investigated whether supplementation of piglets' diets with L-carnitine improves their growth after weaning. In two trials, piglets of the first litters of primiparous sows (trial 1) and the second litters of the same sows (trial 2) were divided into four groups: group 1, piglets of control sows, fed a control diet; group 2, piglets of control sows fed a diet supplemented with 30 mg L-carnitine/kg; group 3, piglets of L-carnitine-treated sows, fed a control diet; group 4, piglets of L-carnitine-treated sows fed a diet supplemented with 30 mg L-carnitine/kg. Mean initial body weights of the piglets of the four groups were identical. They were 8.5 kg in trial 1 and 12.5 kg in trial 2. Diets were fed ad libitum over a period of 35 days. Piglets from sows treated with L-carnitine did not differ in body weight gains, feed intake and gain : feed ratio from those of control sows. In trial 1, piglets supplemented with L-carnitine had higher body weight gains (p < 0.005) and showed a tendency towards a higher gain : feed ratio (p = 0.09) than piglets fed the control diets. In trial 2, no significant difference in these parameters emerged between piglets fed the diet supplemented with L-carnitine and those fed the control diet. In conclusion, this study shows that dietary L-carnitine treatment of sows does not improve the growth potential of their piglets after weaning under the conditions of equal initial body weights. The study also shows that L-carnitine supplementation of their diets improves the growth performance in light piglets of primiparous sows.     

不同赖氨酸水平的低蛋白质日粮对泌乳母猪生产性能和氮排泄量的影响

为探讨低蛋白质日粮赖氨酸水平对泌乳母猪生产性能和氮排泄量的影响,选用3～6胎次、体况相似、预产期相近的60头长大二元杂交母猪,随机分成4个组,每组15头母猪,分别饲喂总赖氨酸水平为0.90％、0.95％、1.00％和1.05％的4种低蛋白质氨基酸平衡日粮,泌乳期21 d.结果表明,0.90％组和0.95％组仔猪窝均增重和平均日增重显著高于1.00％组和1.05％组（P＜0.05）,但0.90％组和0.95％组间、1.00％组和1.05％组间不显著（P＞0.05）;0.90％组母猪泌乳期体重损失显著高于其他3组（P＜0.05）,但其他3组间差异不显著（P＞0.05）;赖氨酸水平对母猪泌乳期日均采食量和断奶发情间隔影响不显著（P＞0.05）;0.90％组和0.95％组氮表观消化率显著高于1.00％组和1.05％组（P＜0.05）、粪氮排泄量显著低于1.00％和1.05％组（P＜0.05）.可见,在低蛋白质氨基酸平衡日粮的条件下,泌乳母猪赖氨酸适宜摄入量为50.05 g/d,即日粮赖氨酸水平为0.95％,能获得较好的生产性能.     

Standardized ileal protein and amino acid digestibility by growing pigs and sows

Experiments were conducted to determine the effect of the physiological condition of swine on standardized ileal digestibility coefficients (SID). The apparent ileal digestibility coefficients were determined for crude protein and amino acids in six feed ingredients (corn, barley, wheat, soybean meal, canola meal, and meat and bone meal) in growing pigs and in gestating and lactating sows. Growing pigs and lactating sows were given free access to their diets, whereas gestating sows were allowed to consume only 2 kg of feed daily. The nonspecific (basal) endogenous losses of protein and amino acids were determined under similar feeding regimens after feeding a protein-free diet. The SID for crude protein and amino acids were calculated by correcting the apparent ileal digestibility coefficients for the nonspecific endogenous losses of protein and amino acids. With a few exceptions, there were no differences (P > 0.05) in the SID for crude protein and amino acids between growing pigs and lactating sows. Overall, gestating sows had higher (P < 0.05) SID for crude protein and all amino acids, except for tryptophan and aspartate, compared with growing pigs. Likewise, the SID of most amino acids obtained by gestating sows were higher (P < 0.05) than those obtained by lactating sows. Interactions (P < 0.05) between animals and diets were observed for gestating sows compared with growing pigs as well as gestating sows compared with lactating sows. As a consequence, it is not possible to extrapolate data from one feed ingredient to another. On most occasions, the lowest SID among the indispensable amino acids was calculated for threonine, valine, and lysine. It is concluded that gestating sows fed 2 kg of feed per day have higher standardized digestibility coefficients than do growing pigs and lactating sows given free access to their diets. This difference may be due to differences in daily feed intake rather than to the physiological status of the animals.     

Analysis of Possible Influence of Conjugated Linoleic Acid on Growth Performance and Losses of Piglets

The aim of this work was to evaluate the effect of supplementing the feed ration for lactating sows with the conjugated linoleic acid (CLA) on the growth performance and losses of piglets from birth to weaning. The monitoring comprised 20 litters in control and 20 litters in experimental group of Czech Large White × Czech Landrace hybrid combination sows. The control group was given a standard feed mixture for lactating sows, and experimental group was fed with the feed mixture supplemented with 2% of CLA, from the day of farrowing to the weaning of piglets, that is for the time of 28 days. The results of the experiment indicate the significantly better parameters of the numbers of reared piglets in the experimental group and the related lower level of losses of piglets from birth to weaning (p < 0.01). However, the feed mixture for lactating sows enriched in conjugated linoleic acid had no significant effect on the growth performance of piglets from birth to weaning (p > 0.05). Sows in the experimental group showed earlier onset of post‐partal oestrus after weaning of piglets (p < 0.05). These findings demonstrate that the supplementation of diet for lactating sows with CLA can improve survival of piglets from birth to weaning and shortening of weaning‐to‐oestrous interval in sows.     

Effect of dietary supplementation of oregano essential oils to sows on colostrum and milk composition, growth pattern and immune status of suckling pigs

This study evaluated the effects of supplementing sow diets with oregano essential oils (OEO) during gestation and lactation on sow colostrum and milk composition and on the growth pattern and immune status of suckling pigs. A total of 70 second-parity sows were randomly assigned to 1 of 2 gestation dietary treatments within 24 h after service: control (CON) or CON + 250 mg/kg of OEO (OREG). In lactation, sows were again assigned to either the CON or OREG dietary treatment. Thus, the lactation treatments were CON-CON, CON-OREG, OREG-CON, and OREG-OREG. Colostrum and blood samples were collected from 6 sows per lactation dietary treatment. Thymus lymphocyte (T lymphocyte) subpopulations (γδ, cluster of differentiation 8, and 32 cluster of differentiation 4) were enumerated in blood and mammary secretions along with IGF-1, IgG, and IgA concentrations. Piglet growth rate were determined from 18, 17, 17, and 18 litters from the CON-CON, CON-OREG, OREG-CON, and OREG-OREG lactation dietary treatments, respectively. Growth rates were determined in 630 piglets, and piglets were individually identified and weighed on 1, 5, 9, 12, 16, and 19 d of age. Oregano essential oil supplementation during gestation or lactation had no effect (P > 0.05) on GE, CP, GE:CP, GE:fat, and IGF-1 in sow milk. Reductions of the fat percentage in milk on d 7 (P < 0.05) and d 14 (P = 0.07) were found in sows supplemented with OEO during lactation compared with those in the CON treatment. Milk from sows supplemented with OEO during lactation had the greatest number of T lymphocytes compared with those in the lactation CON treatment on d 14 of lactation (P < 0.01). The number of T lymphocytes in milk was greater for sows in the CON-OREG treatment compared with those other treatments on d 14 of lactation (P < 0.05). Energy intake was greater on d 1 to 5 in piglets from sows fed OEO during gestation than those from sows in the CON treatment (P < 0.05). A trend (P = 0.10) for greater milk intake was observed in piglets from sows supplemented with OEO during gestation compared with those from sows in the CON treatment. Similarly, a tendency for an increase in ADG on d 1 to 5 was found in piglets from sows supplemented with OEO during gestation compared with those from sows in the CON treatment (P = 0.10). Insulin-like growth factor-1 at birth and on d 7 and 14 of lactation did not differ among piglets from sows assigned to the different dietary treatments. Oregano essential oil supplementation of sow diets did not affect (P > 0.05) immunoglobulin concentrations in piglets after suckling. Supplementing sow diets with OEO during gestation or lactation did not affect (P > 0.05) the T lymphocytes, percentage of T-lymphocyte subpopulations, and natural killer cell activity of piglets during lactation. Supplementing sow diets with 250 mg/kg of OEO during gestation and lactation did not affect the growth potential of and immune responses in suckling piglets.     

中药渣对泌乳母猪及其仔猪血浆生化参数和抗氧化能力的影响

本试验旨在比较研究中药渣和发酵中药渣对泌乳母猪及其仔猪血浆生化参数和抗氧化能力的影响,为其在母猪饲粮配方中的应用提供依据。试验选用2~4胎次、预产期相近的二元母猪60头,随机分为3组,每组20头。3组在基础饲粮中分别添加2 kg/t米糠(对照组)、2 kg/t中药渣制剂(中药渣组)和2 kg/t发酵中药渣制剂(发酵中药渣组)。从产前21 d开始饲喂,到产后28 d结束。分别于母猪产后1、7、14和21 d,每组随机选取6头母猪,耳缘静脉采血;于仔猪7、14和21日龄,每组随机选取6头仔猪,前腔静脉采血。所采血样分离血浆,测定生化参数和抗氧化指标。结果表明:与对照组相比,中药渣组母猪产后7 d的血浆总蛋白(TP)和球蛋白(GLB)含量以及14 d的血浆GLB含量均显著降低(P0.05),产后1 d的血浆碱性磷酸酶(ALP)、过氧化氢酶(CAT)活性和总抗氧化能力(T-AOC),7 d的血浆丙氨酸氨基转移酶(ALT)和ALP活性,14 d的血浆ALT和ALP活性,21 d的血浆ALT活性均显著升高(P0.05);发酵中药渣组母猪产后1 d的血浆天门冬氨酸氨基转移酶(AST)、CAT活性和T-AOC,14 d的血浆AST和ALP活性均显著升高(P0.05);中药渣组14日龄仔猪的血浆ALP活性和丙二醛(MDA)含量均显著降低(P0.05),14日龄的血浆T-AOC显著升高(P0.05);发酵中药渣组7日龄仔猪的血浆ALP活性和T-AOC均显著升高(P0.05),14日龄仔猪的血浆MDA含量显著降低(P0.05)。上述结果表明,母猪饲粮中添加中药渣或发酵中药渣可影响泌乳母猪及其仔猪的机体代谢,增强机体抗氧化能力。     

低蛋白质补充合成氨基酸饲粮对肉仔鸡生长性能、氮排泄及胴体品质的影响

本研究分2个试验,旨在探讨低蛋白质补充合成氨基酸饲粮对肉仔鸡生长性能、氮排泄和胴体品质的影响.试验1选用600只1日龄爱拔益加肉仔鸡(公母各占1/2),分1～21 d,22～42 d和43～49 d 3个阶段饲养,饲粮共设5个处理,粗蛋白质水平分别为:生长前期(1～21 d):22.8%、21.9%、21.0%、19.5%和19.0%;生长中期(22～42 d):20.1%、18.8%、17.8%、16.5%和16.0%;生长后期(43～49 d):18.0%、16.9%、15.9%、15.0%和13.8%.各个处理蛋氨酸、赖氨酸和苏氨酸水平均满足NRC(1994)肉仔鸡营养需要.试验2的5组肉鸡饲粮的蛋白质水平与试验1的生长前期和生长中期饲粮相同,同时补充了足够的合成氨基酸以满足肉仔鸡对所有可消化必需氨基酸的需要量.结果表明:降低饲粮粗蛋白质水平同时补充合成氨基酸不影响试验1各个阶段肉仔鸡的生长性能(P>0.05).当以可消化氨基酸为基础配制饲粮时(试验2),生长前期肉仔鸡的日增重和饲料转化效率得到显著改善(P<0.01),但生长中期和生长全期肉仔鸡日增重和饲料转化效率差异不显著(P>0.05).降低饲粮粗蛋白质水平线性增加了试验1中肉仔鸡的脂肪沉积率(P<0.05),但对其他胴体指标没有显著影响(P>0.05).氮排泄随饲粮粗蛋白质水平的降低而线性减少(P<0.01).此外,降低饲粮粗蛋白质水平还降低了试验2中肉仔鸡血浆甘氨酸和苯丙氨酸的含量(P<0.05).综上所述,降低肉仔鸡饲粮粗蛋白质水平同时补充合成氨基酸可获得使用高蛋白质饲粮时的生长性能和胴体品质.     

植物小肽替代部分鱼粉和豆粕对1～2胎母猪繁殖性能以及仔猪活力的影响

试验旨在研究妊娠后期和哺乳期母猪饲粮中添加植物小肽对1~2胎二元杂种母猪繁殖性能以及初生仔猪活力的影响。采用单因素试验设计,选取40头妊娠90 d的二元杂种母猪(杜洛克伊大白,1~2胎),按随机区组法分为2个处理,每个处理20个重复,每个重复1头母猪。对照组饲喂商品哺乳母猪饲粮(含2%鱼粉),植物小肽组饲喂2%植物小肽(替代1%豆粕和1%鱼粉)。试验期共45 d(从妊娠90 d至21 d断奶)。试验结果表明,两个处理组母猪繁殖性能差异不显著(P>0.05),但与对照组相比,植物小肽组弱仔减少了0.55头(P>0.05),木乃伊胎提高了0.20头(P=0.080)。植物小肽组仔猪初生窝重增加了1.26 kg(P>0.05),初生个体重增加了0.13 kg(P=0.077)。植物小肽组哺乳仔猪死淘率和腹泻率分别比对照组低31.01%和64.14%。两个处理组初生仔猪活力无显著差异(P>0.05)。综上所述,在本试验条件下,1~2胎母猪妊娠后期和哺乳期饲粮中添加2%植物小肽替代部分鱼粉和豆粕不影响母猪繁殖性能,还能一定程度增加仔猪初生重,对仔猪活力无影响。     

Nutritional strategies to cope with reduced litter weight gain and total tract digestibility in lactating sows

Twelve lactating sows were used to evaluate the effects of reducing dietary crude protein (CP) (14% vs. 12%) and increasing neutral detergent fibre (NDF) levels (18% vs. 22%) on litter performance, total tract apparent digestibility and manure composition in a 4 × 4 latin square arrangement during a 36‐day lactation period. Diets were isoenergetic (2.9 Mcal ME/kg) and had similar total lysine content (0.9%). In addition, a second aim was to compare a reference external marker method (Cr₂O₃) with an internal feed marker [acid‐insoluble ash (AIA)] for the calculation of apparent total tract digestibility of nutrients in lactating sows. The reduction of dietary CP level in lactating sows had no effect on either live‐weight or backfat thickness or apparent total tract digestibility of nutrients. However, the piglets' average daily gain (ADG) was reduced in low dietary CP diets, which suggests that sows reduced milk production due to an underestimation of certain essential amino acid requirements (e.g. valine). The increase of dietary NDF level did not affect sow and litter performance. Nevertheless, the total tract apparent digestibility of organic matter, CP and carbohydrates was reduced, and ether extract digestion was increased in high NDF compared to normal NDF diets equally balanced for ME and lysine content. The coefficients of total tract apparent digestibility of nutrients in lactating sows were greater when using AIA compared to Cr₂O₃ marker, regardless of dietary CP or NDF level, but their coefficients of variation were lower in the former than in the latter. In lactating sows, a trade‐off between litter performance and nutrient digestion is established when reducing dietary CP or increasing NDF levels while maintaining similar lysine content through synthetic amino acids and balancing metabolizable energy through dietary fat sources.     

Effects of the Ratio of n-6:n-3 Polyunsaturated Fatty Acids in the Maternal Diet on Immunoglobulins, Fatty Acid Composition, and Performance of Lactating Sows and Suckling Piglets under Conditions of Low Maternal Energy Intake

This experiment was conducted to investigate the effects of different ratios of n-6:n-3 polyunsaturated fatty acids (PUFA) in sow diets on the performance of lactating sows and their piglets at low digestible energy intakes.Twenty-one pregnant Landrace sows were assigned to one of three diets from day 108 of gestation until weaning (26 to 29 d),containing n-6∶n-3 PUFA ratios of 3∶1,8∶1 and 11∶1.The effects on sow and litter production traits and on sow body condition were examined.There were no differences among treatments in daily feed intakes or in changes in sow weight and back-fat levels during lactation.Litter size,litter weight at birth and weaning and litter average daily weight gain were also unaffected by treatment.As expected,large differences were observed in n-6 and n-3 fatty acids in the colostrum and plasma of sows and piglets (P ＜ 0.01 ).The ratio of n-6∶n-3 PUFA the diet was positively correlated with those in colostrum,sow plasma and piglet plasma ( R2 =0.55,0.80 and 0.80,respectively).Sow plasma insulin and IGF-I levels at weaning were unaffected by the treatments.Plasma leptin ( P ＜ 0.05) concentrations were increased in sows fed the diet with a n-6∶ n-3 ratio of 8∶1.Immunoglobulin concentrations in colostrum were not altered by dietary treatment.Plasma IgG concentrations at d 14 were highest in piglets from sows fed the 8∶1 ratio of n-6∶n-3.Furthermore,this group had the highest IgA concentrations at day 21 of lactation compared with the other two groups ( P ＜ 0.05 ).In summary,our study demonstrated that at low digestible energy levels,altering the ratio of n-6∶n-3 PUFA in the diets for lactating sows affected immune components and the fatty acid composition of lactating sows and their piglets.Further studies are needed to examine whether higher levels of fat supplementation than those used in the present study ( 1.5％ ) can successfully enhance performance.     

低蛋白饲粮补充4种氨基酸对肉用羊增重与肉质中氨基酸含量及血清学的影响

本试验旨在研究不同水平低蛋白饲粮补充过瘤胃氨基酸对育肥杜寒杂交肉用母羊增重、血清中蛋白与激素指标、肌肉中氨基酸含量和肉品质的影响,探索育肥肉羊饲粮低蛋白质含量的理论价值和应用效果.选用150只体重相近4月龄育肥杜寒杂交肉用母羊,随机分成5组,每组3个重复,每个重复10只羊.对照组饲喂粗蛋白质水平为16％的饲粮,试验组饲...