Journal of animal science最新文献

Negative social behaviours between pigs can cause stress, which can compromise welfare. There has been significant interest in exploring the effect of diet on negative social behaviours and the wider social behaviour repertoire of pigs. The aim of this study was to determine the effects of dietary Lysine (Lys) and Tryptophan (Trp) levels on the social behaviour of commercially housed pigs. A total of 2,293 PIC Camborough barrows with a mean starting weight of 11.87 ± 1.35 kg were used in a randomised complete block design with a 2×3 factorial arrangement, with 16 replicates per treatment, of the following factors: 1) Standardised ileal digestible Lys levels: 100% Lys = diets with 100% PIC requirement at the midpoint of the growth phase (Lys 100) vs 80% Lys = diets with 80% PIC requirement at the midpoint of the growth phase (Lys 80); and 2) Trp to Lys ratio of 0.210, 0.185 or 0.160. Pigs were randomly allocated across the 6 treatments over 2 starting dates. Behaviour and lesion data were collected. There was an effect of Lys (P=0.032) on ear biting behaviour, with pigs on the Lys 80 treatments showing a higher level of ear biting behaviour. We also found an effect of the Lys score week interaction on the proportion of pens showing ear lesions (P<0.001) and an effect of the Lys Trp interaction (P=0.030) and the Lys score week interaction (P=0.0104) on the proportion of pens showing severe ear lesions. In conclusion, the lysine content of feed can affect the social behaviour of pigs, specifically ear biting, in commercial conditions.

This study compared different levels of dietary zinc oxide (ZnO) on mitochondria ATP synthesis and the cellular and systemic redox balance in weaned pigs. One hundred twenty weaned piglets (7.96 ± 1.17 kg, 21 days of age) were randomly allocated in one of three diets containing different Zn levels (as ZnO); 100 (100Zn), 1000 (1000Zn) and 3000 mg/kg (3000Zn), and were slaughtered at day 21, 23, 35 or 42 for the collection of blood and liver samples. Dietary copper (Cu) levels were constant at 131 mg/kg. Hepatic mitochondrial concentrations of Zn and Cu, hepatic mitochondria respiration, antioxidant response and the hepatic expression of related genes were analyzed. Piglets fed 3000Zn had the highest Zn (P < 0.01) and the lowest Cu concentrations (P = 0.01) in hepatic mitochondria. The hepatic oxygen consumption rate for maximal respiration was the highest in 3000Zn piglets (P < 0.05) whereas hepatic cytochrome c oxidase activity tended to be lower (P = 0.06) and intracellular ATP concentrations was the lowest (P = 0.01). Mitochondrial Cu/Zn superoxide dismutase (Cu/Zn-SOD) activity was the lowest (P < 0.01) and glutathione peroxidase (GPx) activity tended to be the lowest (P = 0.07) for 3000Zn piglets. The mRNA expression of the antioxidant related genes copper chaperone for superoxide dismutase (CCS) was highest (P = 0.01) in 3000Zn piglets and tended to be the highest (P = 0.07) for glutathione synthetase (GSS). Plasma carbonyls concentrations (P = 0.02) and GPx activity (P = 0.01) were the highest while SOD activity was not impacted (P = 0.55) in 3000Zn piglets. In conclusion, supplementing 3000 mg Zn/kg had detrimental impacts on mitochondria Zn and Cu homeostasis, resulting in a dysfunctional mitochondria respiratory chain and disturbed antioxidant response in post-weaning piglets.

Many subjective methods exist to assist producers in evaluating temperament. Use of a pen test, which allows behavior to be observed in a non-restrained setting, may be an effective method to evaluate temperament by allowing more variation among animals to be expressed as compared to a restrained test. The objective of this study was to analyze video recordings of penned calves to determine whether the repertoire of behaviors they expressed were adequately captured by their individual (IPS) and group (GPS) pen scores. In each of 3 yr, 40 predominantly Angus commercial Bos taurus heifers, 2-wk post weaning, were assessed monthly in 3 consecutive months (recording periods). After routine handling through a weigh crate and squeeze chute, each heifer was released individually into a pen (12 x 6 m). Their response to 30 s of human presence within the pen was evaluated. They were then joined in groups of four in a larger (12 x 8 m) pen and re-evaluated for 30 s in a group setting. An IPS and GPS was assigned using an ethogram ranging from 1 (docile) to 6 (aggressive). This interaction was also video recorded. Using the videos, the explicit behaviors captured by each pen score were investigated using Noldus Observer software. Data were analyzed with ANOVA using SAS. Within each recording period, the concordance of pen scores with the repertoire of behaviors expressed were compared. In the group setting, heifers could not be clearly distinguished on video and were instead assigned the average GPS of the group. Heifers with higher IPS and average GPS categories had larger flight zone sizes and reached faster paces for longer periods of time. Furthermore, heifers with lower IPS appeared more neutral to the presence of a human and moved around less often. Ethograms for pen score successfully delineated the temperament of heifers. The use of such scores can provide a valuable on-farm assessment of cattle behavior during routine handling.

Thirty-six Merino wethers (10-month-old) were fed ad libitum for 30 days two diets;1) low metabolizable energy diet (LME; 30% lucerne: 70% cereal chaff) and 2) high ME diet (HME; 40% rolled barley grain: 50% lucerne: 10% cereal chaff). Effects of diet on dry matter intake (DMI), metabolizable energy intake (MEI), liveweight (LWT), average daily gain (ADG), carcass lean or fat gain, liver and empty rumen weight and plasma metabolites were analysed. A membrane enriched protein fraction of rumen epithelium isolated enzymatically from whole depth rumen wall was quantified for each sheep using tandem mass tag mass spectrometry (TMT-MS). The presence or absence of acetylation of lysine residues on identified proteins was counted and the position of the lysine acetylation recorded. In lambs fed the HME diet, DMI (P<0.001), MEI (P<0.001), ADG (P<0.001), fat (P<0.001) and lean gain (P<0.001), as well as liver (P<0.001) and empty rumen (P<0.009) weight were greater than those fed the LME diet. Plasma glucose (P<0.001) and β hydroxybutyrate (P<0.001) at 3 and 5 h after feeding was greater in HME diet than in the LME fed lambs. Changes in rumen epithelium protein abundance in the LME versus HME fed lambs were associated with metabolism in the peroxisome, protein processing in the endoplasmic reticulum (ER), valine, leucine and isoleucine degradation and carbon metabolism. Acetylation of lysine was detected in enzymes involved in glycolysis, tricarboxylic acid (TCA) cycle and fatty acid (FA) metabolism. Quantitative differences in the abundance of rumen epithelium proteins that carry out intracellular processes of energy expenditure were associated with the concentration of ME (MJ/ kg DM) in the diet of growing lambs. The detection of lysine acetylation sites suggests a difference in the ME of the diet regulates enzymatic activity in central metabolic pathways in the rumen epithelium cells.

Prolactin has traditionally been associated with milk production, but recent studies identify prolactin as having many other functions. These include a role in pelage growth, sweating, immune function, metabolism and water/electrolyte balance. A signature of HS is a rise in prolactin concentrations so the question arises as to whether this hormone has a particular function in relation to response to or mitigation of HS. Thus, prolactin plays a multifaceted role in the physiological and behavioral responses of livestock to HS, contributing to their ability to cope with warmer temperatures and maintain homeostasis. A major advance in recent years is the identification of the SLICK gene in cattle, being a mutation in the prolactin receptor. It is responsible for a phenotype of short, shiny coat. SLICK confers heat resilience and offers a realistic means of mitigating HS by introgression into cattle without the mutation. The purpose of this article is to ascertain what functions prolactin may have in the response to HS. It appears that prolactin may be involved in many of the physiological processes that are affected by HS, but it is clear that definitive evidence of cause/effect are yet to be discerned.