支链氨基酸在泌乳母猪营养中的研究现状

综述了支链氨基酸（BCAA）的生理功能，同时阐述了BCAA之间及其与其他氨基酸之间的关系，并重点介绍了BCAA在泌乳母猪中的营养研究现状。     

缬氨酸在泌乳母猪饲粮中的应用研究进展

缬氨酸是三大支链氨基酸(BCAA)之一,具有调控动物蛋白质合成、生长代谢、机体组织修复并提供能量等生物学功能.在泌乳母猪饲粮中添加缬氨酸可提高母猪采食量、泌乳量,改善乳品质.本文主要综述了在泌乳母猪饲粮中添加缬氨酸对母猪生产性能、泌乳性能以及对仔猪生长发育的影响,旨在为缬氨酸在泌乳母猪生产中的应用提供理论参考.     

妊娠及泌乳母猪赖氨酸需要量的研究进展

赖氨酸是母猪第一限制性氨基酸,随着母猪繁殖效率提高,其需要量显著增加。妊娠及泌乳是母猪重要的两个不同生理阶段,相互影响,母猪赖氨酸需要量呈现动态的变化过程。文章总结了近10年妊娠及泌乳母猪赖氨酸需要量的研究报道和行业标准表明:母猪在妊娠后期的赖氨酸需要量显著高于前期,不同阶段、胎次和体况赖氨酸需要量也不同,其适宜剂量范围为妊娠前期12~15 g/d,后期为18~22 g/d;泌乳母猪最大化采食量是制定泌乳期赖氨酸需要量的重量依据,母猪胎次、目标仔猪性能、体重损失及断奶后发情间隔影响泌乳母猪的赖氨酸需要量,其适宜剂量范围为55~70 g/d,赖氨酸含量增加的同时考虑不同生理阶段氨基酸模式的差异。     

繁殖母猪的能量和蛋白质营养(续完)

泌乳母猪的营养　　 能量需要量和妊娠母猪一样 ,用于估计泌乳母猪能量需要量的基本数据见表 1。显而易见 ,最重要的变异因子是母猪的产奶量水平。母猪的产奶量很难测定 ,通常是通过窝增重来进行估计 (Ｎｏｂｌｅｔ和Ｅｔｉｅｎｎｅ,1 989;表1 )。引起泌乳母猪奶产量及进而引起泌乳母猪的能量需要量发生变化的因素可见Ｅｔｉｅｎｎｅ等 (1 999)及Ｎｏ ｂｌｅｔ(1 999)的综述。图 2所示为能量需要量随窝重增长而发生的变化。窝增重从每天 2 0 0 0克增加到每天3 0 0 0克 ,母猪代谢能需要量将从每天 80兆焦增至每天 1 0 5兆焦 ,或者说相当于常…     

泌乳母猪赖氨酸需要量研究进展

赖氨酸作为母猪日粮中一种重要的限制性氨基酸对母猪繁殖性能和泌乳潜力的发挥具有重要的生物学作用,在设计母猪日粮时赖氨酸水平是必须考虑的一个重要参数.本文总结了近30年来泌乳母猪赖氨酸需要量的研究结果,由于初产母猪与经产母猪赖氨酸需要量存在差异,因此,本文分别阐述其赖氨酸需要的研究进展,并讨论了影响泌乳母猪赖氨酸需要的因素,目的是为泌乳母猪日粮中合理应用赖氨酸提供理论依据和实用参考.     

泌乳母猪对芳香族氨基酸的需要量

泌乳母猪对苯丙氨酸(Phe)和酪氨酸(Tyr)的需要量,曾用直接试验测定,估计总芳香族氨基酸(TAAA)需要量为日粮的0.70～1.04%。美国全国科学研究委员会(1979)推荐,每天饲喂5.5公斤谷物大豆饼粉日粮的成龄泌乳母猪,其需要量为0.85%(46.8克/天)。为了更加清楚地确定泌乳母猪对芳香族氨基酸需要量,选用6头以往繁殖性能良好的约克夏×兰德瑞斯母猪(第5～7产)进行了试验。基础日粮含0.30%芳香     

泌乳母猪赖氨酸营养需要的研究进展

泌乳母猪饲养是养猪生产的重要环节之一。由于现代母猪饲养管理方式和品种选育造成的基因型改变等导致其营养需要量也发生变化。赖氨酸作为泌乳母猪最重要的氨基酸一直得到营养学家的关注。本文综述了近20年来泌乳母猪赖氨酸的研究进展和实际条件下运用模型确定的赖氨酸需要量,以期为实际生产服务。     

母猪泌乳期日粮中添加脂肪不会影响日采食量

添加脂肪是调整泌乳期日核能量含量以提高母猪在此期间能量摄入量的一个方法。另一种方法是采用一定的饲喂方法来提高母猪的泌乳期日采食运。高产高泌乳量母猪对能量的需要量是很高的。通常情况下，泌乳母猪不能通过自主采食获取所需的饲料量来满足这些能量需要量，因此母猪泌乳期内的体重就会减轻。然而，可以做到使母猪泌乳期内的体重减轻达到最小而不影响母猪的性能。     

母猪赖氨酸需要量的研究进展

赖氨酸作为母猪第一限制性氨基酸,对母猪繁殖性能和泌乳潜力的充分发挥具有重要的作用。本文主要从母猪氨基酸研究特点、研究现状,赖氨酸需要量的测定方法、测定指标以及母猪在妊娠期和哺乳期对赖氨酸的需要量进行综述,为养猪生产实践中母猪饲粮的合理配制与科学饲养提供参考。     

泌乳母猪饲喂量的确定

泌乳母猪对能量、蛋白质、赖氨酸(以及其他养分)的需要量，取决于其体重、泌乳量和乳汁成分以及其所处的环境和管理条件。所以，几乎每头母猪的能量和养分需要量都各不相同，并且在整个泌乳期内也有变化。表1指出了分娩时体重175千克、21天泌乳期内不失重(A组)和失重10千克(B组)情况下哺乳10头仔猪、仔猪平均日增重150(A1与B1)、200(A2与B2)或250(A3与B3)克时的泌乳母猪，对能量和养分的需要量估值。     

泌乳母猪支链氨基酸的营养生理作用及需要量

支链氨基酸（ＢＣＡＡ）是畜禽的必需氨基酸，对畜禽具有重要的营养生理作用。作者着重阐述支链氨基酸对泌乳的特殊作用，泌乳母猪对支链氨基酸的需要量，以及支链氨基酸及其代谢产物对蛋白质合成和降解的影响。     

Efficiency of food utilization by pregnant and lactating sows. 2. The influence of isocaloric diets with different protein levels on pregnancy and lactation

The efficiency of utilization of feed energy as digestible, metabolizable and net energy is similar in pregnant and lactating sows irrespective of the stage of these physiological conditions. This efficiency with the value of about 71% resembles the one found in the growing and fattening pigs, which enables us to use, for this category of animals, the same system offered evaluation and of the energy requirements based on fat nutritive units. The maintenance energy requirement expressed in ME varies from 467 kJ/kg 0.75 in pregnant sows to 512 kJ/kg 0.75 in lactating sows, for the suckling piglets having intermediary value of 498 kJ/kg 0.75. The efficiency of utilization of diets protein for maintenance and for synthesis is also similar for these categories of pigs, varying from 71% in lactating sows to 75-76% in pregnant sows. In suckling piglets we had recorded an efficiency of DCP utilization which varies parabolically with size of the ingesta and therefore with that of weight gain. The DCP maintenance requirement expressed in g N dig./kg 0.75 varies within narrow limits between 0.345 g N in suckling piglets 0.380 g N in pregnant sows; In lactating sows we have detected an intermediary value of 0.355 g N. Based on these experimental data and also using recent experimental results obtained by Schiemann and Beyer (1984) regarding the energy and N content of the foetuses, of the organs of reproductions and of milk, we could calculate the energy and protein requirements. These requirements when compared with the values used in our country show us higher values of energy in pregnant and lactating sows and lower values of protein for the same categories, including the piglets, where we have also found lower values for the energy too.     

酪酪肽生理功能及其在哺乳母猪养殖中的应用前景

采食量是制约哺乳母猪生产性能发挥的重要因素.酪酪肽作为一种典型的抑食因子,在调节摄食、消化道功能方面具有重要作用,成为关注的新热点.本文主要从酪酪肽的主要生物学特性和生理功能两方面进行综述,并对其在哺乳母猪养殖中的应用前景进行展望.     

Improving efficiency of sow productivity: nutrition and health

This reviews research focused to understand the nutrient requirement and balance to meet the needs of fetal growth, mammary growth, and milk production. This summary will handle how feeding strategies can be adjusted according to the nutrient needs for a sow to enhance productivity and health. Most research data used in this summary are based on the studies conducted by the authors between 1996 and 2013. Nutrient requirements of sows are affected by stage of gestation and parity of sows. Dietary antioxidant concentrations need to be re-evaluated for its sufficiency in sow diets especially to prevent excessive oxidative stress during late gestation and lactation. When feeding sows, consideration of phase feeding of gestating sows and parity feeding of lactating sows could enhances production longevity and health of sows. Use of selected nutrients and additives seems to help productivity and health of sows.     

Comparative protein and amino acid digestibilities in growing pigs and sows.

An experiment was conducted to compare apparent total tract protein digestibilities and apparent ileal digestibilities of protein and amino acids in growing pigs and adult pregnant and lactating sows. Twelve growing pigs and 12 sows were used and surgically fitted with simple T-cannulas at the distal ileum. Six experimental diets based on corn, barley, wheat, soybean meal, canola meal, or meat and bone meal were formulated, and each diet was fed to growing pigs, gestating sows, and lactating sows for 7 d. Chromium oxide was included in all diets as an indigestible marker (.25%) for calculating nutrient digestibilities. Fecal material was collected on d 5 of each feeding period by grab sampling, and ileal samples were collected for 12 h/d during the last 2 d of each feeding period. Apparent fecal protein digestibilities for all feed ingredients were higher (P < .05) in gestating and lactating sows compared to growing pigs, but no differences between the two groups of sows were observed (P > .05). At the distal ileum, no differences (P > .05) in protein digestibilities were detected between sows and growing pigs regardless of feed ingredient. For all feed ingredients tested, lactating sows had apparent ileal digestibilities of most amino acids that were two to six percentage units higher than those obtained in growing pigs, but not all of the differences were significant. Gestating sows had digestibilities of most amino acids that were intermediate between those of growing pigs and lactating sows. The combined results from the six feed ingredients showed that lactating sows had higher (P < .05) digestibilities of all indispensable amino acids except arginine, and gestating sows had higher (P < .05) digestibilities of five of the indispensable amino acids than did growing pigs. The results of this experiment indicate that apparent fecal protein and apparent ileal amino acid digestibilities obtained in growing pigs are not always representative of digestibilities in either gestating or lactating sows.     

The effect of short-term phytase supplementation on the apparent total tract digestibility of calcium and phosphorus and the reproductive performance of late gestation and lactating sows fed diets without mineral phosphorus

The objective of this study was to measure apparent total tract digestibility (ATTD) of Ca and P as well as reproductive performance in late gestation and lactating sows supplemented with a novel phytase and to compare the response to phytase supplementation between late gestation and lactating sows. A total of 45 late gestation sows and 45 lactating sows were used in experiments 1 and 2, respectively, in a completely randomized design. The sows were provided with a control diet or the control diet supplemented with 187.5 or 375 FYT phytase/kg feed for 10 days. The diets were prepared according to the formulas in use for production but without any inorganic P supplement. Titanium dioxide was included at 3 g/kg feed as an indigestible marker. Each dietary treatment was replicated with 15 sows individually housed in farrowing stalls. The sows were allowed to adapt to the experimental diets for 5 days before a 5-d fecal collection by grab sampling, and the performance of the sows and their litters were measured until weaning. The results showed that the ATTD of Ca increased linearly (P < 0.001), while the ATTD of P increased both linearly and quadratically (P < 0.01) with increasing supplementation of phytase in both late gestation and lactating sows. There was no significant effect of phytase on the ATTD of dry matter, crude protein, and gross energy, and the performance of the sows and their progenies. The phytase added at 187.5 and 375 FYT/kg feed released 0.07% and 0.10% digested P, respectively, in late gestation sows, which compared with 0.09% and 0.12% digested P in lactating sows. In conclusion, a novel phytase at 187.5–375 FYT/kg feed could release 0.07–0.12% digestible P for sows. It appeared that using the P digestibility values of feed ingredients listed by NRC to formulate a diet for sows might overestimate dietary P supply and a greater response to phytase supplementation could be expected in lactating sows than in late gestation sows.     

Energy requirements of pregnant and lactating sows

The energy requirement of pregnant and lactating sows is derived on the basis of extensive experimental studies of the energy metabolism (indirect calorimetry, slaughtering) according to the factorial method. For the first reproduction cycle (RC) 0.41 MJ metabolizable energy (ME) or 0.29 MJ net energy fat, pig (NEFpig) resp. were necessary for energy maintenance requirement for pregnant and lactating sows and, depending on age, 0.44 MJ ME or 0.31 MJNEFpig in the second or third RC and 0.47 MJ ME/kg LW0.75.d or 0.33 MJ NEFpig/kg LW0.75.d in the 4th-8th RC. A linear increase of up to 6% of the energy requirement caused by pregnancy between the 85th and 115th day of pregnancy is taken into consideration. Energy requirement per 1 MJ retention both in pregnancy and lactation is 1.45 MJ ME or 1.03 MJ NEFpig, per 1 MJ milk yield it is 1.33 MJ ME or 0.91 MJ NEFpig. 1 MJ body energy for milk yield corresponds to 1.20 MJ ME or 0.82 MJ NEFpig. Equations describing energy retention in the products of conception, uterus and udder are established as well as equations characterizing the connections between live weight gain or loss and energy content of the gain or loss.     

Porcine Luteal Function in Relation to IGF-1 Levels Following Ovulation During Lactation or After Weaning

Contents This study presents relationships between peripheral progesterone and Insulin-like Growth Factor-1 (IGF-1) concentrations during the early luteal phase in sows. Data were derived from three experiments, one with primiparous weaned sows (n = 21) and two with multiparous sows that either ovulated during lactation (n = 23) or after weaning (n = 12). The sows that ovulated during lactation did so due to an intermittent suckling regime (inhibition of suckling for 12 h each day from day 14 of lactation) or due to treatment with PG600. IGF-1 concentrations varied considerably among experiments, and were the lowest in the multiparous sows, regardless of whether they were weaned or lactating: 68 ± 5 and 85 ± 8 ng/ml in the two experiments with multiparous sows vs 188 ± 15 ng/ml in the primiparous sows. Progesterone concentrations were lowest for the lactating sows. Overall, the increase in progesterone during the early luteal phase was strongly correlated with IGF-1 concentrations (r = 0.7). However, the correlation was low in multiparous lactating sows (r = 0.28; p < 0.10) and nonsignificant in multiparous weaned sows (r = 0). The weaned multiparous sows had IGF-1 levels comparable to lactating multiparous sows, but higher progesterone levels. In conclusion, these data show a positive relationship between peripheral IGF-1 and progesterone concentrations in vivo during the early luteal phase. In lactating sows, IGF-1 concentrations are probably a limiting factor for progesterone secretion, although other factors may be involved.     

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.     

Plasma levels of cortisol in zero-weaned and lactating sows during the first two weeks post partum

The object of this investigation was to study the plasma levels of cortisol during the day of parturition and the first two weeks post partum in primiparous zero-weaned (weaned within 12 hr after birth) and lactating sows. Fourteen primiparous sows were used. They were grouped as follows: group A, (3 sows) zero-weaned, ovulating; group B, (4 sows) zero-weaned, anovulatory; group C, (4 sows) lactating with normal litter size; group D, (3 sows) lactating with small litter size. The peripheral plasma levels of cortisol were determined by radioimmunoassay throughout the experimental period,The peripheral plasma levels of cortisol were significantly higher in the anovulatory than in the normally ovulating sows. The lactating sows had almost the same levels of cortisol as the zero-weaned sows with anovulatory estrus. There was no difference in cortisol levels between sows nursing small or normal litters.It may be concluded that elevated plasma levels of cortisol might be one of several factors inhibiting the LH surge during the first estrus after zero-weaning. No relationship was found between cortisol levels and number of suckling piglets.