Ovarian activation delays in peripubertal ewe lambs infected with Haemonchus contortus can be avoided by supplementing protein in their diets.

BACKGROUND: The ewe lamb nutritional and physiological state interfere with the ovarian environment and fertility. The lack or excess of circulating nutrients reaching the ovary can change its gene expression. A protein deficiency in the blood caused by an Haemonchus contortus abomasal infection is detrimental to the organism's development during puberty. The peripubertal period is a time of intensive growth that requires a high level of nutrients. An essential feature controlling pubertal arousal and female reproductive potential is ovarian follicle growth activation. Protein supplementation improves the sheep's immune response to helminthic infections. We aimed to determine if supplementing protein in infected ewe lambs' diet would impact the ovarian environment leading to earlier ovarian follicle activation than in infected not supplemented animals. METHODS: We fed 18 Santa Ines ewe lambs (Ovis aries) - bred by the same ram - with either 12% protein (Control groups) or 19% protein (Supplemented groups) in their diets. After 35 days of the diet, they were each artificially infected or not with 10,000 Haemonchus contortus L3 larvae. Following 77 days of the diet and 42 days of infection, we surgically collected their left ovaries and examined their genes expression through RNA sequencing. RESULTS: We found that protein supplementation in infected animals led to an up-regulation of genes (FDR p-values < 0.05) and biological processes (p-value cut-off = 0.01) linked to meiotic activation in pre-ovulatory follicles and primordial follicle activation, among others. The supplemented not infected animals also up-regulated genes and processes linked to meiosis and others, such as circadian behaviour. The not supplemented animals had these same processes down-regulated while up-regulated processes related to tissue morphogenesis, inflammation and immune response. CONCLUSION: Diet's protein supplementation of peripubertal infected animals allowed them to express genes related to a more mature ovarian follicle stage than their half-sisters that were not supplemented. These results could be modelling potential effects of the interaction between environmental factors, nutrition and infection on reproductive health. When ovarian activation is achieved in a timely fashion, the ewe may generate more lambs during its reproductive life, increasing sheep breeders' productivity.

Evaluation of a cattle rapid test for early pregnancy diagnosis in sheep.

The early pregnancy diagnosis allows optimizing production and timely management correction, with a greater reproductive output of livestock. The Idexx Rapid Visual Pregnancy Test® consists of an ELISA for visual reading which does not require the use of readers in the laboratory, with satisfactory pregnancy diagnoses at 28 days of pregnancy in cattle. Therefore, the aim of this study was to evaluate this rapid test and to verify the most appropriate day for the diagnosis of pregnancy in the ovine species. For this purpose, 98 serum samples from pregnant sheep and 36 from non-pregnant were used, with duplicate samples, and diagnosis was confirmed by ultrasound examination, used as the gold standard. The numbers of positive samples obtained at 26, 28, and 30 days of pregnancy were 26, 27, and 45, respectively. The Rapid Visual Pregnancy Test correctly identified 100% of the samples as positive at pregnancy of days 26, 28, and 30. The sensitivity and specificity of the test were also 100%. The Idexx Rapid Visual Pregnancy Test, initially indicated for cattle, is effective for the detection of pregnancy in the ovine species, enabling diagnosis of pregnant sheep from the 26th day of pregnancy.

Visual ELISA for detection of pregnancy-associated glycoproteins (PAGs) in ewe serum.

The aim of the present study was to evaluate the efficiency of visual ELISA-PAG for early pregnancy diagnosis based on the presence of PAG (pregnancy-associated glycoprotein) using sheep blood serum. Experiment 1: 140 ewes were divided into three groups with different stages of pregnancy. In the first group, 41 pregnant ewes were sampled at 26, 28, 30, and 32 days of pregnancy; in the second group, 65 ewes (49 pregnant with 30 days and 16 non-pregnant) were sampled; in the third group, 34 non-pregnant ewes were sampled. Experiment 2: 10 pregnant ewes were sampled weekly from day 35 of gestation until day 70 post-partum to verify the total period in which PAG can be detected in the blood serum by the test. Transrectal ultrasound was used as a gold standard. The detection or non-detection of PAG was analyzed by the logistic model PROC GENMOD of SAS; differences were detected by the chi-squared test. In group 1, there were no differences between the results from 28, 30, and 32 days of gestation, but samples from 30 days were easier to interpret in comparison to 28 days, with a sensitivity of 97.56%. In the second group, using 65 sheep, visual ELISA-PAG showed 100% sensitivity and 93.75% specificity, which indicates the diagnosis of an animal as a false positive. In the third group, 97.06% of the sheep were confirmed as negative and 2.94% as positive, again indicating the presence of a false positive. In 100% of the sheep, the PAG remained in the blood circulation throughout the antepartum period until birth and seven days post-partum, declining thereafter. Based on our results, the visual ELISA-PAG is an effective method for the early diagnosis of pregnancy in sheep and can be performed from day 30 of gestation.