Effect of Negative Energy Balance on Plasma Metabolites, Minerals, Hormones, Cytokines and Ovarian Follicular Growth Rate in Holstein Dairy Cows

Introduction

The aim of this study was to evaluate the effect of negative energy balance (NEB) on the final growth of the dominant ovarian follicle in Holstein cows.

Material and Methods

Cows at 14 to 21 d postpartum from an intensive dairy farm were randomly selected and allocated into a positive energy balance group (PEB, with β-hydroxybutyric acid (BHBA) level < 1.2 mmol/L, n = 15) and an NEB group (BHBA > 1.2 mmol/L, n = 15). Plasma samples were collected at 21, 50 and 55 d postpartum to assess the concentrations of energy metabolites, minerals, hormones and cytokines. Ovaries were examined by transrectal ultrasound on days 50 and 55 (120 hours later) to evaluate the diameter of the largest follicle.

Results

Compared with PEB cows, there were a more severe body condition loss and a lower milk yield in NEB cows (P < 0.05) and these had greater concentrations of plasma BHBA, non-esterified fatty acids, triglycerides, urea nitrogen, growth hormone, interleukin 6, and fibroblast growth factor 21 and lesser concentrations of plasma glucose, total cholesterol, insulin, insulin-like growth factor 1, insulin-like growth factor binding protein 3, leptin, brain-derived neurotrophic factor and angiopoietin-like protein 8 on d 21 (P < 0.05), while plasma minerals were not affected by energy status (P > 0.05). These changes persisted until the end of the study period (50–55 days postpartum) resulting in a lower follicular growth rate for cows in the NEB than the PEB group.

Conclusion

These observations indicate that follicular growth rate is associated with measurable changes in energy metabolite, hormone and cytokine concentrations caused by early postpartum NEB.

Long noncoding RNA and mRNA profiling of hypothalamic-pituitary-mammary gland axis in lactating sows under heat stress

Heat stress (HS) seriously affects sow lactation performance and Long non-coding RNAs (lncRNAs) play vital roles in the regulation of transcription and post transcription. However, the mechanism of lncRNAs expression affecting lactation performance on the hypothalamus-pituitary-mammary axis of sows is still unclear. In this study, we performed RNA sequencing and bioinformatics analysis of the hypothalamus, pituitary, and mammary gland tissues of lactating sows under HS and thermal comfort. In total, the analysis identified 658, 6021, and 6745 differently expressed (DE) mRNAs, 26, 126, and 169 DE lncRNAs between comparison groups in the hypothalamus, pituitary, and mammary glands, respectively. The hormone genes and most DE mRNAs encoding heat shock protein were differently expressed in the HS group. In addition, 2, 60, and 86 pairs of DE lncRNAs and mRNAs correlation were observed in those tissues, respectively. Some lncRNAs may be involved in the regulation of lactation performance in the HS sows.

Effect of supplementation of niacin on physiological and blood biochemical parameters in crossbred cows during heat stress

In order to investigate the effect of different levels of niacin supplementation on physiological and blood biochemical parameters during heat stress period (April to August; 120 days), eighteen crossbred early lactating cows (2nd to 4th lactation; 11.56±1.74 days in milk) were divided into three groups of six animals each. The basal ration was fed same to all cows (Green fodder, straw and concentrate was fed as per NRC, 2001), except the addition of niacin @ 600 and 800 mg/kg dry matter intake (DMI) in T1 and T2 groups, respectively. The temperature humidity index (THI) was calculated at 07:30 am and 02:30 pm daily. Fortnightly physiological parameters were recorded and blood was collected from the jugular vein at day 0 and subsequently at 15–day interval from all the experimental animals to study blood biochemical parameters. The results revealed that animals were in either moderate or severe stress at morning, whereas during afternoon the animals were in very severe stress during the entire trial. Supplementation of niacin @ 800 ppm niacin decreased significantly skin temperature, respiration rate, cortisol, super oxide dismutase (SOD) and catalase (P<0.05). Plasma NEFA was significantly low in both niacin supplemented groups (P<0.05). Plasma urea was found significantly (P<0.05) high in T2 (26.59) in comparison to control (24.90) and T1 (25.37). It is concluded that 800 ppm niacin supplementation to lactating crossbred cows resulted in better stress alleviation as indicated by the improved biomarker values viz., SOD, catalase, cortisol and skin temperature.

Impact of maternal malnutrition during the periconceptional period on mammalian preimplantation embryo development

During episodes of undernutrition and overnutrition the mammalian preimplantation embryo undergoes molecular and metabolic adaptations to cope with nutrient deficits or excesses. Maternal adaptations also take place to keep a nutritional microenvironment favorable for oocyte development and embryo formation. This maternal-embryo communication takes place via several nutritional mediators. Although adaptive responses to malnutrition by both the mother and the embryo may ensure blastocyst formation, the resultant quality of the embryo can be compromised, leading to early pregnancy failure. Still, studies have shown that, although early embryonic mortality can be induced during malnutrition, the preimplantation embryo possesses an enormous plasticity that allows it to implant and achieve a full-term pregnancy under nutritional stress, even in extreme cases of malnutrition. This developmental strategy, however, may come with a price, as shown by the adverse developmental programming induced by even subtle nutritional challenges exerted exclusively during folliculogenesis and the preimplantation period, resulting in offspring with a higher risk of developing deleterious phenotypes in adulthood. Overall, current evidence indicates that malnutrition during the periconceptional period can induce cellular and molecular alterations in preimplantation embryos with repercussions for fertility and postnatal health.

Effect of growth hormone administration to mature miniature Brahman cattle treated with or without insulin on circulating concentrations of insulin-like growth factor-I and other metabolic hormones and metabolites

Previously, we determined that a primary cause of proportional stunted growth in a line of Brahman cattle was related to an apparent refractoriness in metabolic response to GH in young animals. The objective of this study was to determine the effect of administration of GH, insulin (INS), and GH plus INS to mature miniature Brahman cows (n = 6; 9.7 ± 2.06 y; 391 ± 48.6 kg) and bulls (n = 8; 9.4 ± 2.00 y; 441 ± 54.0 kg) on circulating concentrations of metabolic hormones and metabolites, primarily IGF-I and IGF-I binding proteins. We hypothesized that IGF-I secretion could be enhanced by concomitant administration of exogenous GH and INS, and neither alone would be effective. Animals were allotted to a modified crossover design that included four treatments: control (CON), GH, INS, and GH + INS. At the start of the study, one-half of the cattle were administered GH (Posilac; 14-d slow release) and the other one-half served as CON for 7 d. Beginning on day 8, and for 7 d, INS (Novolin L) was administered (0.125 IU/kg BW) twice daily (7:00 AM and 7:00 PM) to all animals; hence, the INS and GH + INS treatments. Cattle were rested for 14 d and then were switched to the reciprocal crossover treatments. Blood samples were collected at 12-hour intervals during the study. Compared with CON, GH treatment increased (P < 0.01) mean plasma concentrations of GH (11.1 vs 15.7 ± 0.94 ng/mL), INS (0.48 vs 1.00 ± 0.081 ng/mL), IGF-I (191.3 vs 319.3 ± 29.59 ng/mL), and glucose (73.9 vs 83.4 ± 2.12 mg/dL) but decreased (P < 0.05) plasma urea nitrogen (14.2 vs 11.5 ± 0.75 mg/dL). Compared with INS, GH + INS treatment increased (P < 0.05) mean plasma concentration of INS (0.71 vs 0.96 ± 0.081 ng/mL), IGF-I (228.7 vs 392.3 ± 29.74 ng/mL), and glucose (48.1 vs 66.7 ± 2.12 mg/dL), decreased (P < 0.01) plasma urea nitrogen (13.6 vs 10.4 ± 0.76 mg/dL), and did not affect GH (13.5 vs 12.7 ± 0.95 ng/mL). In the miniature Brahman model, both the GH and GH + INS treatments dramatically increased circulating concentrations of IGF-I in mature cattle, suggesting that this line of Brahman cattle is capable of responding to bioactive GH.