Acute immobilization stress in prone position in susceptible Pietrain and resistant Duroc pigs. I: comparison of protein degradation in Duroc and Pietrain pigs' skeletal muscle and liver

The experiment was conducted to determine the relationship between lysosomal proteinase activities in skeletal muscle and liver of stressed pigs. Six‐month‐old Duroc (D) and Pietrain (P) pigs were randomly assigned to either control (group I) or stressed groups (5 min of stress, group II; 15 min of stress, group III; 30 min of stress, group IV; 60 min of stress, group V). At slaughter, the longissimus dorsi muscle and the liver were taken. The tissues were analysed for cathepsin D, acid autolytic activities without and with pepstatin (inhibitor of cathepsin D) and leupeptin (inhibitor of cysteine proteinases). Both tissues were also analysed for RNA, DNA and protein content. The acute immobilization stress in the prone position caused changes in longissimus dorsi muscle in DNA (26% decrease in D and 35% increase in P pigs), functional cell size, protein/10³DNA (FCS) (34% increase in D and 25% decrease in P pigs), increase in acid autolytic activity (AAA) (by 48.3%), pepstatin insensitive acid autolytic activity (PIA) (by 111.8%), leupeptin insensitive acid autolytic activity (LIA) (by 35.8%) in D, but in P pigs by 13.5%, 16.6% and 54%, respectively. The interaction between strain of pigs and stress was also observed, mostly in DNA and AAA's. In the liver, RNA was decreased by 10% in D and by 12.3% in P pigs, DNA by 13% and 24% in D and P pigs, FCS was increased by 13.2% in D and by 22.7% in P pigs; the activity of cathepsin D (CatD) and pepstatin sensitive cathepsin D (PSCatD) increased after 15 min of stress by 9.2% and 9.3% and LIA by 13.7% in D pigs but in P pigs the maximal increase was after 15 min of stress in AAA by 10.3%, in PIA by 13.6% and in LIA by 3.2%. The experiment showed that the proteinase activities in the two different strains of pigs were different. The highest changes were in AAA's in the longissimus dorsi muscle and in CatD and PSCatD in the liver. There was more CatD in the longissimus dorsi muscle and liver of D than P pigs. Although it should be taken with caution, this suggests that other proteinases may be also responsible for the catabolism of proteins.     

Acute immobilization stress in prone position in susceptible Pietrain and resistant Duroc pigs. II. Glycolytic metabolism in Piettrain and Duroc skeletal muscle and liver

Duroc (D) and Pietrain (P) pigs were used to study the effect of acute immobilization stress on carbohydrate metabolism. Changes in the activities of several glycolytic enzymes and the content of glycogen in longissimus dorsi muscle (LDM), glycogen content in the liver and glucose level in plasma were observed. The glycogen level in LDM of pigs was about five times higher in P pigs compared with D ones. The immobilization stress of 15 min caused a decrease of glycogen LDM content by 27% in D and by 44% in P pigs. In the liver, these changes were 75% in P pigs, but in D pigs the glycogen content was lowered during the time of experiment by 37% (control versus 60 min stress). Plasma glucose level was elevated by 118% in D and by 50.5% in P pigs after 15 min of immobilization stress. The activities of the glycolytic enzymes investigated changed in different way in LDM: the PGluM decreased by 20% in D and by 19% in P pigs; the GPI by 8.5% in both strains of pigs; the PFK and PK were higher in D than in P pigs (some statistically significant differences between PK activities of control and 15‐, 30‐ and 60‐min‐stressed animals); the ALD activity was similar in both investigated strains of pigs and LDH was lower in D than in P pigs. It can be assumed that the changes led to the new homeostasis connected with the stress to which the pigs were subjected.     

二花脸和皮特兰猪应激状态下行为和血液生化指标的变化

对氟烷显性基因纯合子（Hal^NN）二花脸猪和氟烷隐性基因纯合子（Hal^nn）皮特兰猪分别进行翻背和装车实验,分析装车前、后血液生理生化指标的变化。结果显示：（1）3、10、17日龄二花脸猪的翻背实验评分（Backtest score,BS）均显著低于同日龄皮特兰猪（P〈0.001）;（2）二花脸猪在装车前血浆皮质醇水平显著高于皮特兰猪（P〈0.01）,肌酸激酶活性（Creatine kinase,CK）显著低于皮特兰猪（P〈0.001）,而乳酸脱氢酶活性（Lactate dehydrogenase,LDH）品种间差异不显著;（3）装车使皮特兰猪血浆皮质醇水平显著上升（P〈0.05）,而二花脸猪血浆皮质醇水平在装车前后差异不显著;血浆中CK和LDH活性在装车前后无显著变化。结果表明,氟烷显性基因纯合子二花脸猪应对翻背和装车应激的敏感性均低于氟烷隐性基因纯合子皮特兰猪。     

The influence of immobilization stress on natural killer cytotoxic activity in halothane susceptible and resistant pigs.

In halothane-susceptible (Hal+) and halothane-resistant (Hal-) Belgian Landrace pigs, the influence of immobilization stress on cytotoxic activity of natural killer (NK) cells was evaluated. Four hour immobilization causes biphasic changes in cytotoxicity, i.e. an initial increase followed by a subsequent depression. In both groups of pigs stress-induced suppression of NK cell activity lasted for several days in the post stress period. Throughout the experiment, i.e. before, during and after stress, the level of cytotoxicity was higher in Hal+ than in Hal- pigs.     

Perioperative plasma cortisol concentration in the horse

The cortisol response to anaesthesia and surgery was studied in 2 groups of horses undergoing either abdominal or non-abdominal surgery. The preoperative mean plasma cortisol concentration (pcc) of 381.7 nmol/l (s.d. 254.7) was markedly higher in the abdominal group than the early-morning mean pcc of 115.6 nmol/l (s.d. 78.4) in the non-abdominal group. During halothane anaesthesia and surgery the mean pcc increased significantly (p < 0.05) from the preoperative mean of 119.2 to 215.9 nmol/l (s.d. 79.8) after 30 min of surgery in the non-abdominal group. In the abdominal group a decrease occurred after induction of anaesthesia and surgical preparation, but increased during surgery to a mean pcc of 418.1 nmol/l (s.d. 236.5). In the postoperative period a large decrease in the mean pcc occurred after 24 h in the abdominal group. It was only after 60 h that the pcc (153.2 nmol/l) equalled the pcc of the non-abdominal group (171.4 nmol/l) at 24 h. The slow decline over 60 h could be an indication of the prolonged recovery associated with abdominal surgery in the horse.     

The effect of electro-ejaculation on aversive behaviour and plasma cortisol concentration in rams

Electro-ejaculation is used in rams to collect semen for fertility and bacteriological evaluation. Concern has been expressed about animal welfare implications of EE. Two experiments were carried out to compare the aversiveness of electro-ejaculation, part shearing and free movement, and to determine the changes in plasma cortisol concentration produced by electro-ejaculation, shearing and lateral restraint. In the aversion test, transit time was greater (p<0.003) for rams subjected to part shearing than free movement. There were no major differences in the transit time between the rams subjected to electro-ejaculation and those subjected to part shearing or free movement. In addition, there was no significant difference in the effort required to move rams from the three treatment groups into or through the experimental route. These results suggest that electro-ejaculation is no more aversive than part shearing. There were no significant differences in the cortisol response of the rams subjected to electro-ejaculation, shearing or lateral restraint, indicating that there were no significant differences in the distress caused by the three procedures.     

The effect of electro-ejaculation on aversive behaviour and plasma cortisol concentration in rams

Electra-ejaculation is used in rams to collect semen for fertility and bacteriological evaluation. Concern has been expressed about animal welfare implications of EE. Two experiments were carried out to compare the aversiveness of electro-ejaculation, part shearing and free movement, and to determine the changes in plasma cortisol concentration produced by electro-ejaculation, shearing and lateral restraint. In the aversion test, transit time was greater (p<0.003) for rams subjected to part shearing than free movement. There were no major differences in the transit time between the rams subjected to electro-ejaculation and those subjected to part shearing or free movement. In addition, there was no significant difference in the “effort” required to move rams from the three treatment groups into or through the experimental route. These results suggest that electro-ejaculation is no more aversive than part shearing. There were no significant differences in the cortisol response of the rams subjected to electro-ejaculation, shearing or lateral restraint, indicating that there were no significant differences in the distress caused by the three procedures.     

The effect of acute restraint stress on regional brain neurotransmitter levels in stress-susceptible pietrain pigs

Concentrations of noradrenaline (NA), adrenaline (A), dopamine (DA), 5-hydroxytryptamine (5-HT), the DA metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) and the main 5-HT metabolite 5-hydroxyindole-3-acetic acid (5-HIAA) were measured using HPLC in 16 brain areas of control and immobilized Pietrain pigs. The animals were immobilized for 15, 30 and 60 min in the prone position. Control pigs showed patterns of regional distribution of brain monoamines similar to those described for rats, dogs and Duroc pigs. However, the absolute values of NA and A in the hypothalamus and preoptic area were much higher than those in rats and dogs, but similar to those in Duroc pigs. The concentrations of dopamine and its metabolites DOPAC and HVA were highest in the caudate nucleus, the nucleus accumbens, the olfactory tubercle and the ventral tegmental area. The distributions of serotonin and its metabolite 5-HIAA were similar in all examined structures. DOPAC/DA and HVA/DA ratios were higher in the cornu ammonis, the hippocampus posterior and the raphe nuclei than in other structures, which suggests brain structure-related differences in dopamine turnover. The greatest decreases in NA and A content were observed in the hypothalamus, the preoptic area and the olfactory tuberculum during the first 30 min of immobilization stress. 5-HT turnover was increased in the raphe nuclei, while DA turnover was affected in the raphe nuclei, the septum, the substantia nigra and the olfactory tubercle. We suggest that acute immobilization stress caused differences in regional patterns of brain biogenic amines, thereby maintaining adequate transmitter levels during stress in stress-susceptible pigs.     

Dietary tryptophan effects on plasma and salivary cortisol and meat quality in pigs

Four experiments were conducted to determine the effects of supplemental Trp on meat quality, plasma and salivary cortisol, and plasma lactate. Experiment 1 was a preliminary study to measure plasma cortisol concentrations in 4 barrows (50 kg of BW) that were snared for 30 s at time 0 min. Pigs were bled at -60, -30, -15, 2, 4, 6, 8, 10, 15, 20, 25, 30, 45, 60, 90, and 120 min. Plasma cortisol was near maximum 10 min after the pigs were snared. In Exp. 2, 20 barrows (50 kg of BW) were allotted to a basal corn-soybean meal diet or the basal diet with 0.5% supplemental l-Trp for 5 d. After the 5-d feeding period, pigs were snared for 30 s and bled at -10, 0, 2, 4, 6, 8, 10, 15, 20, 25, 30, 45, 60, 90, and 120 min after snaring. Pigs fed the diet with supplemental Trp had a lower (P < 0.01) mean plasma cortisol than pigs fed the basal diet. Plasma lactate also was decreased (P < 0.07) by supplemental Trp. In Exp. 3, the same pigs and treatments were used as in Exp. 2, but 5 pigs were snared and 15 pigs adjacent to those being snared were bled to determine if pigs are stressed when they are adjacent to pigs being snared. For pigs adjacent to snared pigs, the area under the curve (P < 0.06) and mean for plasma cortisol was lower (P < 0.01) in pigs fed Trp relative to those fed the basal diet. In Exp. 4, 90 barrows (initial BW of 106 kg) were allotted to 6 treatments in a 3 x 2 factorial arrangement. Three diets with Trp (basal diet, basal supplemented with 0.5% Trp for 5 d, or pigs fed the basal diet with a 0.1 g/kg of BW Trp bolus given 2 h before slaughter) were combined with 2 handling methods (minimal and normal handling). Dressing percent, 24-h pH, and 24-h temperature were reduced in the minimally handled pigs (P < 0.10) compared with the normally handled pigs. Pigs fed Trp in the diet relative to those fed the basal diet had increased 45-min temperature, Commission Internationale de l'Eclairage (CIE) redness (a*) and yellowness (b*) values, and drip and total losses (P < 0.10). Tryptophan in bolus form decreased 45-min pH in the minimally handled pigs but increased 45-min pH in the normally handled pigs (handling x Trp bolus interaction, P = 0.08). Tryptophan in the diet increased CIE lightness (L*) in minimally handled pigs but decreased CIE L* in the normally handled pigs (handling x Trp diet interaction, P = 06). No other response variables were affected by handling method or Trp. Results indicate that Trp decreases plasma cortisol but has no positive effect on meat quality.     

Effect of African trypanosomiasis on plasma cortisol and thyroxine concentration in goats

Changes in plasma cortisol and thyroxine (T4) levels were measured weekly in female goats experimentally infected with Trypanosoma congolense. Values for plasma cortisol (range 10 to 25 nmol litre-1) and T4 (range 65 to 120 nmol litre-1) were within normal ranges in all goats before infection and in control animals throughout the 24 weeks of study. Cortisol/T4 ratios of 0.23 to 0.15 (or 1:4 to 1:7) were obtained. In the infected goats a significant increase in cortisol and decline in T4 were simultaneously observed within one week of the onset of parasitaemia and fever. A peak cortisol/T4 ratio of 2.0 (2:1) was obtained four weeks after infection when cortisol levels rose to 59.0 +/- 8.9 nmol litre-1 and T4 declined to 29.4 +/- 2.2 nmol litre-1. Thereafter the mean levels fluctuated but remained high (over 30 nmol litre-1) for cortisol and low (under 50 nmol litre-1) for T4 up to 18 weeks after infection. Both hormones tended to return to normal levels towards the end of the study. The changes in mean cortisol levels showed a significant inverse correlation with changes in T4 (r = -0.57, P less than 0.001, n = 26). It is suggested that in trypanosomiasis, hypothalamic stress causes increases in plasma cortisol levels and at the same time suppresses the activity of the thyroid gland.     

皮特兰猪的氟烷基因检测与分子选育

以PCR-RFLPs法为检测方法,针对氟烷基因开展无应激皮特兰猪的分子选育,共检测从2003-2007年若干世代共28批次皮特兰猪。结果显示,在所检测的共994头样本中,具NN基因型的为361头,具Nn基因型的为374头,具nn基因型的为259头。试验结果表明,随着世代选育的进展,群体中N基因和NN基因型的频率逐渐升高,至第17批次时均达100%,后均维持在较高水平,Hard-Weinberg平衡亦呈现平衡-不平衡-平衡的现象,直至此基因最终在群体中失去平衡。试验结果还表明,利用基因技术对家畜进行分子育种是可行的。     

Estimation of the additive and dominance variances in SA Duroc pigs

The objective of this study was to estimate dominance variance for number born alive (NBA), 21-day litter weight (LWT21) and interval between parities (FI) in South African Duroc pigs. A total of 10,703 NBA, 6883 LWT 21 and 6881 FI records were analysed. Bayesian analysis via Gibbs sampling was used to estimate variance components and genetic parameters. Estimates of additive genetic variance were 0.554, 16.84 and 4.535 for NBA, FI and LWT21, respectively. Corresponding estimates of dominance variance were 0.246, 9.572 and 0.661 respectively. Dominance effects were statistically not significant for all traits studied. Further research utilizing a larger data set is necessary to make concrete conclusions on the importance of dominance genetic effects for the traits studied.     

Genetic correlation between serum insulin-like growth factor-1 concentration and performance and meat quality traits in Duroc pigs

This study was intended to examine whether serum IGF-I concentration is appropriate for use as a physiological predictor for genetic improvement of meat production and meat quality traits in pigs. Heritabilities and genetic correlations were estimated for these traits. The Duroc breed used in this study was selected for seven generations for average daily BW gain (DG) from 30 to 105 kg of BW, loin-eye muscle area (EM), backfat thickness (BF), and intramuscular fat (IMF) content. Serum IGF-I concentration of boars and gilts at the fourth generation of selection and that of boars, gilts, and barrows from the fifth to seventh generations of selection were measured at 8 wk (IGFI-8W) for 832 animals and again at the time they reached 105 kg of BW (IGFI-105KG) for 834 animals. A multivariate REML procedure was used to estimate genetic parameters with a model incorporating generation of selection, sex, common environmental effect of litter, and individual additive genetic effects. Heritability estimates for IGFI-8W and IGFI-105KG were 0.23 +/- 0.02 and 0.26 +/- 0.03, respectively. The estimates of common environmental effect for IGFI-8W and IGFI-105KG were 0.20 +/- 0.02 and 0.03 +/- 0.01, respectively. Positive genetic correlations were estimated between IGFI-8W and DG (0.26 +/- 0.08), EM (0.22 +/- 0.10), and IMF (0.32 +/- 0.10). Moreover, the positive genetic correlation between IGFI-105KG and EM was 0.42 +/- 0.08. These results indicate that serum IGF-I concentration at an early stage of growth was effective for prediction of IMF, but it was not a reliable physiological predictor of genetic merit of meat production traits.