氧化应激与疾病

2．4胎衣不下（RIM） 该症是导致抗氧化状况衰竭的第一步。奶牛RFM可引起子宫内膜炎、连续的卵巢周期延误、妊娠推迟等系列损失。     

The genetic system for reaction of field beans (Phaseolus vulgaris L.) to infection by three physiologic races of Colletotrichum lindemuthianum

Genetic resistance to race alpha of C. lindemuthianum in the nine varieties of beans studied can be accounted for by dominant alleles at either of two loci, which are unlinked and which behave as duplicate factor loci in the classical sense. A similar system of loci governs reaction to races beta and gamma, with evidence favoring multiple allelism and dominance of alleles conferring susceptibility in certain instances in the case of beta. In addition, for reaction to races beta and gamma, there are distinct systems of complementary factors, again with multiple allelism at the beta loci. Finally, there is genetic linkage between genes of the duplicate factor set governing reaction to gamma and genes of the duplicate factor set, and complementary factor set conditioning reaction to beta. The genes that are members of the set(s) pertaining to any one race alone are independent of each other in a linkage sense.Paper based on work conducted by the senior author in partial fulfilment of requirements for the Doctor of Philosophy degree at Michigan State University and supported by the Rockefeller Foundation.Formerly Rockefeller Foundation Student in Crop Science, now Director, Instituto Nacional de Investigaciones Agricolas, Veracruz, Mexico; Professor of Crop Science, Michigan State University; and Research Pathologist, Crops Research Division, Agricultural Research Service, USDA.     

饲料-病原体互作

4调节病原体毒力 机体被病原性微生物侵袭后就会发生感染性疾病。然而仅是传染性微生物存在于机体内并不一定就能导致随后疾病的发生,日粮和营养状态都能对病原微生物的毒力产生影响。4．1坏死性肠炎和产气荚膜梭菌许多梭菌能够分泌强力毒素,能够引起人和动物的诸如破伤风、波特淋菌中毒、产气性坏疽和坏死性肠炎等。产气荚膜梭菌是一种重要的家禽病原菌,如果不加控制,     

Ranch-management factors associated with antibody seropositivity for Neospora caninum in consignments of beef calves in Texas, USA

A study was conducted with a 1998 retained-ownership population of Texas (USA) beef calves to determine the ranch-management practices associated with calf seroprevalence to Neospora caninum. Management practices of 76 Texas ranches that consigned 760 calves to a retained-ownership feedlot program were reviewed from a mailed questionnaire. Ninety-nine of 760 (13%; 95% CI, 9.4%, 17.7%) calves were positive to N. caninum and 59% of the ranches consigned at least one positive calf. In the logistic multiple-regression model which controlled for overdispersion, increased odds of calf-level seropositivity was associated with seasonal calving patterns, with stocking>1cow/calfunit/2.2ha, using a round-bale feeder, allowing wildlife access to the weaning supplement, and self-reared replacement heifers. However, decreased odds of seropositivity was associated with using a cattle-working dog and with using a self-contained cattle feeder. There was substantial overdispersion due to ranch.     

Cross‐sectional observational survey of serum biochemistry values in a population of 69 adult female alpacas (Vicugna pacos) in South Australia

Blood samples were collected from 69 ‘healthy’ female alpacas aged ≥12 months from 11 properties in South Australia. The 10–90 percentile ranges of the 16/19 analytes measured in this sample population were within the published ranges of four healthy alpaca populations from other geographic locations. Marginal exceptions were glutamate dehydrogenase and bicarbonate. Potassium was notably elevated, probably because of haemolysis of some samples. The sample size was insufficient to provide the appropriate statistical power to define diagnostic references ranges according to international standards. The health status of the sample population of alpacas was presumptive based on a physical examination.     

Influence of the Cumulus and Gonadotropins on the Metabolic Profile of Porcine Cumulus–Oocyte Complexes During In Vitro Maturation

The aim of this work was to examine the influence of the cumulus and gonadotropins on the metabolic profile of porcine cumulus oocyte complexes (COCs) during in vitro maturation. Immature COCs were assigned to morphological classes A₁ (with a dense cumulus), A₂ (with a translucent cumulus), B₁ (with the corona radiata), B₂ (with only some remaining cumulus cells) and matured with or without gonadotropins. Glycolysis and ammonia production were higher in the A class COCs; gonadotropins increased both, especially in the A₁ COCs (p < 0.05). The A class COCs had the highest initial protein contents and at the end of in vitro maturation. Furthermore, hormonal stimulation induced a similar increase in protein contents of both A classes (p < 0.05). The neutral lipid content and reactive oxygen species (ROS) levels were similar in the immature oocytes of the COCs of all classes. A reduction was seen in both these variables when maturation proceeded either in the presence or absence of gonadotropins. The cumulus type surrounding the oocyte is related to the metabolism of carbohydrates and amino acids by the COC during in vitro maturation under gonadotropic stimulation. Oocyte lipolytic activity and ROS production appear to be independent of the surrounding cumulus and the presence of gonadotropins.     

Scrotal circumference,bodyweight and semen characteristics in growing dairy-breed natural-service bulls in Tasmania,Australia

Aims: To provide herd managers with a set of decision rules allowing them to predict the likelihood that a juvenile bull is ready for Bull Breeding Soundness Evaluation (BBSE), or breeding, if bodyweight and scrotal circumference are known.

Methods: This was a longitudinal study following two groups of young pasture-fed Holstein and Jersey bulls from northwest Tasmania, Australia. Individual scrotal circumference, bodyweight and semen characteristics were recorded at 6–8 weekly intervals, from 6–18 months of age. Classification and regression tree analyses were used to predict the probability that a bull had ≥70% normal sperm morphology based on scrotal circumference and bodyweight measurements.

Results: Overall 1,661 scrotal circumference and bodyweight measurements were obtained, and 518 semen samples from 356 bulls were assessed for sperm morphology, from 16 examination sessions that took place between 29 May 2015 and 17 August 2016. Classification and regression tree analyses generated a decision tree for Holstein bulls with four node endpoints, and for Jersey bulls with three node endpoints. Diagnostic test performance showed that for Holstein bulls, using the node endpoints of scrotal circumference ≥27?cm and bodyweight ≥349?kg, 98% had ≥70% normal sperm (positive likelihood ratio 10.4; 95% CI?=?2.7–41), and using the node endpoints of scrotal circumference ≥27?cm and bodyweight between 282–349?kg, 89% had ≥70% normal sperm (positive likelihood ratio 1.6; 95% CI?=?0.9–2.6). For Jersey bulls, using the node endpoints of bodyweight ≥259?kg and scrotal circumference ≥29?cm, 88% had ≥70% normal sperm (positive likelihood ratio 3.4; 95% CI?=?1.6–7.0).

Conclusions: This study provides a set of relatively simple decision rules based on bodyweight and scrotal circumference measurements that allows herd managers to assess the likelihood that juvenile bulls are ready for BBSE or breeding.

Abbreviations: BBSE: Bull breeding soundness evaluation; BRT: Boosted regression tree     

Participation of phosphofructokinase,malate dehydrogenase and isocitrate dehydrogenase in capacitation and acrosome reaction of boar spermatozoa

The aim of this work was to determine the enzymatic activity of phosphofructokinase (PFK), malate dehydrogenase (MDH) and isocitrate dehydrogenase (IDH) in boar spermatozoa and study their participation in bicarbonate‐induced capacitation and follicular fluid‐induced acrosome reaction. Enzymatic activity of these enzymes was determined spectrophotometrically in extracts of boar spermatozoa. Sperm suspensions were incubated in the presence of bicarbonate (40 mM), a well‐known capacitation inducer, or follicular fluid (30%), as an acrosome reaction inducer, and different concentrations of oxoglutarate, oxalomalate and hydroxymalonate, inhibitors of PFK, IDH and MDH, respectively. Capacitation percentages were determined by the fluorescence technique of chlortetracycline (CTC), and true acrosome reaction was determined by trypan blue and differential–interferential contrast, optical microscopy. The activity of PFK in boar spermatozoa enzymatic extracts was 1.70 ± 0.19 U/10¹⁰ spermatozoa, the activity of NAD‐ and NADP‐dependent IDH was 0.111 ± 0.005 U/10¹⁰ and 2.22 ± 0.14 U/10¹⁰ spermatozoa, respectively, and the activity of MDH was 4.24 ± 0.38 U/10¹⁰ spermatozoa. The addition of the specific inhibitors of these enzymes prevented sperm capacitation and decreased sperm motility during capacitation and inhibited the acrosome reaction (AR), without affecting the sperm motility during this process. Our results demonstrate the participation of PFK, IDH and MDH in bicarbonate‐induced capacitation and follicular fluid‐induced acrosome reaction in boar spermatozoa, contributing to elucidate the mechanisms that produce energy necessary for these processes in porcine spermatozoa.