断奶仔猪的营养性应激及其对策

1早期断奶仔猪的应激反应1.1适口性相对较差断奶后,主要能量来源的乳脂由谷物淀粉所替代,可以完全被消化吸收的酿蛋白变成了消化率较低的植物蛋白,并且饲料中还有仔猪几乎不能消化     

调控日粮减轻断奶仔猪营养性应激的途径

1提高日粮中的能量能量是影响断奶仔猪生长性能的关键要素。仔猪断奶后,由于饲料类型和管理条件的改变,使大脑皮质糖苷分泌增加,对饲粮中能量的要求有所增加。适当提高日粮中的能量水平,以保证猪每日所需能量的绝对摄入量,可减少应激。其具体方法为在日粮中添加脂肪,尽管早期断奶仔猪利用脂肪的能力很低,但仍需添加一定油脂便于饲料在加工过程中制粒。由于断奶仔猪料中乳源性成分含量较高,难以制粒,而添加5％～6％脂肪在制粒时可起到润滑作用。但是,在选择油脂时应注意,只有那些能被仔猪消化利用的油脂才能用于仔猪。     

断奶仔猪营养性应激的应对措施

正哺乳仔猪断奶前的营养需要大都由母乳提供,含有丰富的脂肪和易于消化的酪蛋白,其碳水化合物则以乳糖为主,不含淀粉和纤维。断奶后,作为主要能量来源的乳脂则由谷物淀粉所替代,可完全消化吸收的酪蛋白变成了消化率较低的植物蛋白,且饲料中还含有仔猪不能消化的纤维素,与仔猪消化道中的酶系统和生理环境等均不相适应,可引起断奶仔猪出现失重,血糖、胰岛素和生长激素水平、肝     

断奶仔猪营养性应激的应对措施

本文介绍了断奶仔猪的应激反应机制及临床表现,阐述了断奶仔猪营养性应激的应对措施.     

改善仔猪的营养性应激的调控措施

应激是指机体对外界或内部的各种非常刺激所产生的非特异性应答反应的总和。现代养猪生产通过早期隔离断奶技术来提高母猪的年生产力．但仔猪早期断奶时，因心理、环境及营养性应激的影响，常表现为食欲差、消化功能紊乱、腹泻、生长迟滞、饲料利用率低等所谓的仔猪早期断奶综合症。在这些应激因素中，营养性的应激占很重要的原因，[第一段]     

调控应激的营养途径

１能量适当提高日粮中的能量水平，以保证猪每日所需能量的绝对摄入量，可减缓应激（Nienaaber）。由于在日粮中提高了能量浓度，降低了热增耗。在应激畜禽中用油脂代替部分碳水化合物，可使动物获得较高的生产净能，同时改善饲料适口性，并不是应激状态下畜禽对脂肪的需要量增加。具体的方法有：①适当提高日粮的能量浓度；②日粮中添加脂肪。一般认为，在高温条件下，日粮添加２％～３％混合脂肪是提日粮能量水平、稳定猪增长速度的有效措施（JohnGoihl，１９８９），特别在日粮赖氨酸供应不足时，该效果明显；③日粮中添加乳糖、蔗糖。…     

改善仔猪营养性应激的调控措施

应激是指机体对外界或内部的各种非常刺激所产生的非特异性应答反应的总和。现代养猪生产通过早期隔离断奶技术来提高母猪的年生产力，但仔猪早期断奶时，因心理、环境及营养性应激的影响，常表现为食欲差、消化功能紊乱、腹泻、生长迟滞、饲料利用率低等所谓的仔猪早期断奶综合征。在这些应激因素中，营养性的应激占很重要的原因，为保证仔猪顺利地早期断奶，解决好营养性应激是当代养猪科学与动物营养学所关注的热点问题，成为养猪成功的关键环节之一。它不仅影响仔猪的健康与发育，还严重影响以后的生长速度与健康性能。     

断奶仔猪营养性腹泻及其防治措施

随着饲养规模的不断扩大和集约化程度的不断提高,现代养猪生产中已逐步推广和普及仔猪3～5周龄断奶,即通常所谓的早期断奶。早期断奶仔猪由于受心理、环境、营养应激等因素的影响,导致仔猪断奶后易发生消化机能紊乱,出现腹泻。而腹泻又会导致仔猪生长受阻,饲料利用率降低,免疫力下降,抗病力差等,严重时甚至死亡,给养猪生产造成巨大的经济损失。近20多年的研究     

断奶仔猪营养性腹泻及其调控措施

在现代集约化的养猪生产中,实行仔猪早期断奶已经得到了广泛的认可,它不但可以使仔猪通过饲料得到充足的营养来快速的生长发育,而且还可以缩短母猪的泌乳期(或繁殖周期)来提高母猪的生产性能。然而仔猪早期断奶带来的腹泻问题是养猪业面临的又一难题。腹泻不仅造成仔猪的饲料利     

仔猪断奶应激及其营养调控

综述了断奶应激对仔猪的影响,分析了应激发生的原因,阐述了相应的饲养调控措施,以期为早期断奶应激综合症的防治和科学饲养管理断奶仔猪提供理论依据.     

小肽的营养特性及其在仔猪生产中的应用

综述了小肽的营养特性及其在仔猪生产中的应用,旨在为小肽在仔猪生产中合理的应用提供理论依据。     

断奶仔猪的饲喂方案

不管仔猪断奶早与晚,断奶仔猪的饲喂方案和营养策略应彻底地重新考虑,以确保保育期营养方案的成功实施。设计合理的营养方案和饲料预算不能独自确保保育方案的成功,必须配合其它措施。我们正开始明白,不但给幼龄猪喂什么饲料是重要的,而且教它们怎样采食和如何进行管理同样重要。一个成功的保育期饲喂方案包括多种要素,但最重要的是:A)尽可能从体重较重和日龄较大时开始保育;B)尽可能快地从复杂日粮转换为简单日粮;C)给仔猪提供正确的管理措施,使其能迅速找到食物和饮水,并经常调整喂料器,以获得最佳的饲料效率。     

Fasting and refeeding modulate the expression of stress proteins along the gastrointestinal tract of weaned pigs

The gastrointestinal tract (GIT) of young mammals is submitted to aggressions early in life and GIT stress proteins are up-regulated in pigs following weaning. We hypothesized that transient food deprivation may contribute to these changes. Therefore, the effects of fasting and refeeding on GIT stress proteins in weaned pigs were investigated. A complete block experimental design with three groups of five pigs each was set up with the following treatments: A - food offered, B - fasted for 1.5 days, C - fasted for 1.5 days and then re-fed for 2.5 days. After slaughter, the GIT was removed, weighed and sampled. Intestinal villi and crypts were measured and alkaline phosphatase activity was determined. GIT tissue stress protein concentrations were measured by Western blotting. Fasting led to intestinal mucosa and villous-crypt atrophy (p < 0.01) and reduced mucosal alkaline phosphatase total activity in the proximal small intestine (p < 0.05). Heat shock proteins HSP 27 and HSP 90 (but not HSP 70) and neuronal NO synthase (nNOS) increased (p < 0.01) in the stomach, mid-intestine and proximal colon with fasting. Inducible NOS (iNOS) did so in the stomach (p < 0.001). Refeeding partially or totally restored GIT characteristics and stress protein concentrations, except for gastric HSP 90 and iNOS. Significant correlations (p < 0.05 to p < 0.0001) were found among stress proteins, between nNOS and digesta weight, between HSP 27 or HSP 90 and intestinal mucosa weight, and between intestinal or colonic HSP or nNOS and alkaline phosphatase. In conclusion, fasting and refeeding modulate GIT HSP proteins and nNOS in pigs following weaning. Changes in digesta and intestinal mucosa weights and alkaline phosphatase activity may be involved in the modulation of stress proteins along the GIT.     

Vaccination of weaned pigs against oedema disease

The trial was performed in a pig-production unit with high prevalence of postweaning oedema disease (ED). An experimental inactivated VT2e-toxoid vaccine was produced. Two randomised treatment groups of piglets were formed. The animals in one group (n = 351) were vaccinated intramuscularly at 1 week of age with 12.5 micrograms and at 3 weeks of age with 25 micrograms of inactivated VT2e toxin. The other group (n = 350) was placebo treated. We evaluated: average daily nursery weight gain, nursery mortality due to ED, fattening average daily weight gain until slaughter and VT2e-specific antibody titres. Serological tests were performed four times: before first vaccination, at weaning, at the end of nursery period and at an age of 4 month. Vaccination improved nursery average weight gains (301 +/- 31 g/day vs. 278 +/- 41 g/day). Mortality due to edema disease decreased in vaccinates: 0.9% vs. 6.9%. Fattening average daily weight gain until slaughter did not differ between the groups (711 +/- 41 g vs. 708 +/- 46 g).     

Dietary clays alleviate diarrhea of weaned pigs

Two experiments were conducted to determine whether 3 different clays in the nursery diet reduce diarrhea of weaned pigs experimentally infected with a pathogenic Escherichia coli. Weaned pigs (21 d old) were housed in individual pens of disease containment chambers for 16 d [4 d before and 12 d after the first challenge (d 0)]. The treatments were in a factorial arrangement: 1) with or without an E. coli challenge (F-18 E. coli strain; heat-labile, heat-stable, and Shiga-like toxins; 10(10) cfu/3 mL oral dose daily for 3 d from d 0) and 2) dietary treatments. The ADG, ADFI, and G:F were measured for each interval (d 0 to 6, 6 to 12, and 0 to 12). Diarrhea score (DS; 1 = normal; 5 = watery diarrhea) was recorded for each pig daily. Feces were collected on d 0, 3, 6, 9, and 12 and plated on blood agar to differentiate β-hemolytic coliforms (HC) from total coliforms (TC) and on MacConkey agar to verify E. coli. Their populations on blood agar were assessed visually using a score (0 = no growth; 8 = very heavy bacterial growth) and expressed as a ratio of HC to TC scores (RHT). Blood was collected on d 0, 6, and 12 to measure total and differential white blood cell (WBC) counts, packed cell volume (PCV), and total protein (TP). In Exp. 1 (8 treatments; 6 replicates), 48 pigs (6.9 ± 1.0 kg of BW) and 4 diets [a nursery control diet (CON), CON + 0.3% smectite (SM), CON + 0.6% SM, and CON until d 0 and then CON + 0.3% SM] were used. The SM treatments did not affect growth rate of the pigs for the overall period. In the E. coli challenged group, the SM treatments reduced DS for the overall period (1.77 vs. 2.01; P < 0.05) and RHT on d 6 (0.60 vs. 0.87; P < 0.05) and d 9 (0.14 vs. 0.28; P = 0.083), and altered differential WBC on d 6 (neutrophils, 48 vs. 39%, P = 0.092; lymphocytes, 49 vs. 58%, P = 0.082) compared with the CON treatment. In Exp. 2 (16 treatments; 8 replicates), 128 pigs (6.7 ± 0.8 kg of BW) and 8 diets [CON and 7 clay treatments (CON + 0.3% SM, kaolinite, and zeolite individually and all possible combinations to total 0.3% of the diet)] were used. The clay treatments did not affect growth rate of the pigs. In the E. coli challenged group, the clay treatments reduced DS for the overall period (1.63 vs. 3.00; P < 0.05), RHT on d 9 (0.32 vs. 0.76; P < 0.05) and d 12 (0.13 vs. 0.39; P = 0.094), and total WBC on d 6 (15.2 vs. 17.7 × 10(3)/μL; P = 0.069) compared with the control treatment. In conclusion, dietary clays alleviated diarrhea of weaned pigs.     

奶牛的热应激反应及其对策

所谓奶牛的热应激反应，指的就是奶牛由于受到炎热的刺激而引起的一系列的反应。这是因为奶牛体内热量的散发主要靠呼吸器官，而奶牛的呼吸特别恒热，易于发生热应激反应，大量的饲养实践证明，在每年的６～８月间，由于环境气温的升高，奶牛自身肌体的热调节机能开始失调，正常的功能及其激素平衡等遭到破坏，并易发生皮肤代谢受阻，体内物质代谢发生障碍、呼吸急促，心跳加快、体温上升、食欲下降、体重减轻、发情机制紊乱、配种受胎率下降、健康水平低下、抗病能力减弱、犊牛生长缓慢及死亡率增加等症状，而且大量的统计学数字还表明，在…     

Effect of spray-dried plasma and lipopolysaccharide exposure on weaned pigs: II. Effects on the hypothalamic-pituitary-adrenal axis of weaned pigs

A study was conducted with 20 weaned barrows (14 d, 4.98 +/- 0.21 kg) to determine the effect of feeding spray-dried plasma (SDP) after weaning on the pig's stress response to a lipopolysaccharide (LPS) challenge. After weaning, pigs were fed a diet containing 0 or 7% SDP for 7 d. On d 6 after weaning, all pigs were nonsurgically fitted with a jugular catheter. On d 7 after weaning, the pigs were given i.p. injections of either saline or LPS (150 microg/kg BW) followed by serial blood collection every 15 min for a 3-h period. Following the 3-h blood collection, all pigs were killed and tissue was collected for mRNA analysis. Pig weight on d 7 after weaning was not affected by dietary treatment (P > 0.21). Pigs fed the diet with SDP had lower (P < 0.05) levels of hypothalamic corticotropin-releasing hormone (CRH) mRNA, pituitary gland CRH receptor mRNA, and adrenal gland adrenocorticotropin-releasing hormone (ACTH) receptor mRNA. Dietary treatment did not affect pituitary gland proopiomelanocortin (POMC) mRNA. No effect of LPS treatment was observed in any of the mRNA levels examined. For both serum ACTH and cortisol, there was a significant diet x LPS treatment interaction (P < 0.01) such that both the ACTH and cortisol responses to the LPS challenge were greater in the pigs fed the diet with SDP than in the pigs fed the diet without SDP. For pigs given the saline injection, diet did not affect basal serum cortisol concentration; however, basal serum ACTH concentration was lower in those pigs fed the diet with SDP (P < 0.0001). A diet x LPS treatment interaction (P < 0.024) was observed for adrenal gland mRNA expression for steroidogenic acute regulatory (StAR) protein such that the LPS-induced increase in StAR mRNA was greater in the pigs fed SDP than in pigs fed the diet without SDP. These results demonstrate that pigs fed a diet with SDP have an increased activation of the pituitary-adrenal axis following an LPS challenge compared to pigs fed a diet without SDP.     

Effect of spray-dried plasma and lipopolysaccharide exposure on weaned pigs: I. Effects on the immune axis of weaned pigs

A study was conducted with 20 weaned barrows (14 d, 4.98 +/- .21 kg) to determine the effect of spray-dried plasma (SDP) on the pig's immune response to a lipopolysaccharide (LPS) challenge. After weaning, pigs were fed a diet containing 0 or 7% SDP for 7 d. On d 6 postweaning, all pigs were fitted with a jugular catheter. On d 7 postweaning, the pigs were given an i.p. injection of either saline or LPS (150 microg/kg BW) followed by a 3-h blood collection every 15 min. Following blood collection, all pigs were killed and tissue was collected for mRNA analysis. Additionally, the small intestine was collected for measurement of villus height, crypt depth, and villus height:crypt depth ratio (VCR) at three sites (25, 50, and 75% of the total length). Feeding SDP resulted in reduced (P < 0.05) mRNA expression of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) mRNA in the adrenal gland, spleen, hypothalamus, pituitary gland, and liver. Additionally, expression of IL-6 mRNA was reduced (P < 0.05) in the spleen and pituitary gland for pigs fed SDP. For pigs fed the diet with SDP, LPS administration did not affect (P > 0.10) cytokine mRNA expression, whereas LPS reduced expression of TNF-alpha mRNA in the spleen and IL-1beta mRNA in the adrenal gland, spleen, and thymus for pigs fed the diet without SDP. For pigs fed the diet with SDP, LPS caused serum TNF-alpha to increase 150-fold compared to a 60-fold increase for pigs fed the diet without SDP. Similarly, interferon-gamma (IFN-gamma) increased 110-fold for pigs fed the diet with SDP compared to a 16-fold increase for pigs fed the diet without SDP. For pigs fed the diet with SDP, LPS caused major villus atrophy, whereas for pigs fed the diet without SDP, LPS had no effect on intestinal morphology. These results demonstrate that the basal activation of the immune system appears to be less for pigs fed the diet with SDP compared to pigs fed the diet without SDP after weaning. Additionally, for pigs fed the diet with SDP, there appeared to be an overresponse of the immune system following LPS administration, which resulted in major damage to the mucosa of the gastrointestinal tract.