Association between seasonal changes in fatty-acid composition, expression of VLDL receptor and bovine sperm quality.

Reduced reproductive performance of dairy cows during the summer is often associated with elevated temperature. Semen collected and cryopreserved during the summer may be of low quality and might contribute to the compromised fertility of dairy cows during this season. The present study examined the association between seasonality, semen quality and its potential to survive cryopreservation.

Summer heat stress alters the mRNA expression of selective-uptake and endocytotic receptors in bovine ovarian cells.

Summer heat stress (HS) is a major factor in decreased reproductive performance in high-producing dairy cattle, possibly by affecting the steroidogenic capacity of ovarian follicles and ovarian follicular dynamics. In the present study, mRNA expression of cholesterol receptors was determined in bovine ovarian cells. Two endocytotic receptors (very-low-density lipoprotein receptor (VLDLr) and low-density lipoprotein receptor (LDLr)), and two selective-uptake receptors (scavenger receptor class B type 1 receptor (SRB1) and the lipoprotein-receptor-related protein 8 (LRP8)) were evaluated.

Temporal folate status during lactation in mares and growth in foals.

Objective: To identify changes in folate status of mares and foals during lactation and growth, respectively.

Animals: 20 Thoroughbred mares and foals.

Procedures: Pregnant mares, and following foaling the same mares with their foals, were maintained on mixed grass-legume pasture and fed either a traditional dietary supplement rich in sugar and starch (SS) or a dietary supplement high in fat and fiber (FF).

Impaired immune responses in broiler hatchling hindgut following delayed access to feed.

One of the key stimulators of intestinal development in the chick is physical exposure to feed, while feed withholding delays the onset of gut development. A delay of 24-72 h in onset of feeding is quite common in the poultry industry due to variation in hatching time and hatchery treatments. As intestinal development occurs in concert with the development of the gut associated lymphoid tissue (GALT), we investigated the effects of short term feed withholding on development of GALT in broiler hatchlings.

Expression of mRNA of lipoprotein receptor related protein 8, low density lipoprotein receptor, and very low density lipoprotein receptor in bovine ovarian cells during follicular development and corpus luteum formation and regression.

Lipoproteins in the plasma are the major source of cholesterol obtained by the ovarian theca and granulosa cells for steroidogenesis. In this study, we have identified mRNA expression in bovine theca and granulosa cells of two lipoprotein receptors, low density lipoprotein receptor (LDLr) and very low density lipoprotein receptor (VLDLr) in granulosa cells from small antral follicles through preovulatory follicles and in theca cells from large and medium sized antral follicles. In the corpus luteum (CL) both these receptors were found in the developing and differentiating stages whereas only mRNA for VLDLr was detected in the regression stage.

Lipid transport in the developing bovine follicle: messenger RNA expression increases for selective uptake receptors and decreases for endocytosis receptors.

Differences in rates of steroid production and secretion will, eventually, determine the developmental rates of ovarian follicles. The major supply of cholesterol, the precursor for steroid and androgen biosynthesis, to ovarian cells is from circulating lipoproteins via membrane receptors from the low density lipoprotein receptor (LDL) superfamily. This occurs by either endocytosis, which has been described for very low density lipoprotein receptors (VLDLr), for LDL receptors (LDLr), and by the selective uptake pathway described for the scavenger receptor class B type 1 receptor (SRB1) and the recently described ovarian receptor, lipoprotein receptor-related protein 8 (LRP8).

Mucin dynamics in the chick small intestine are altered by starvation.

The absorptive surface of the small intestine is covered by a layer of mucus secreted by goblet cells. The secreted mucins and thickness of the adherent layer influence nutrient digestion and absorption processes as well as the functionality of the mucosa. In this study, methods for the analysis of mucin synthesis and dynamics in the chick small intestine are described.

Ontogeny of brush border carbohydrate digestion and uptake in the chick.

Ingestion of carbohydrates from the small intestine is the major route of energy supply in animals. In mammals these functions develop both pre- and postnatally and are coordinated for the sucking period. In birds, the physiological requirements are different and hatchlings ingest diets rich in complex carbohydrates soon after hatching.

Early posthatch feeding stimulates satellite cell proliferation and skeletal muscle growth in turkey poults.

The effect of early posthatch feeding on skeletal muscle growth and satellite cell myogenesis was studied in turkey poults. Poults were either fed immediately posthatch or food-deprived for the first 48 h and then refed for the rest of the experiment. Body and breast muscle weights were lower in the starved poults than in fed controls throughout the experiment (P < 0.

Na+/glucose co-transporter abundance and activity in the small intestine of lambs: enhancement by abomasal infusion of casein.

The purpose of the present study was to determine the effect of abomasal casein infusion on glucose uptake and abundance of the Na+/glucose co-transporter (SGLT1) 1 in the ovine small intestine. Lambs (body weight 35 (sem 1.0) kg) were surgically fitted with abomasal infusion catheters and were fed diets containing equal portions of wheat hay and cracked maize.

Ethiopian-born and native Israeli school children have different growth patterns.

Objective: Nutrition status of preschool children in Azezo, North West Ethiopia, and Ethiopian-born and native Israeli children aged 7 to 11 y and 12 to 15 y was studied. The aim of the study was to determine the growth patterns of immigrant children after changes in their nutritional habits.

Methods: The Ethiopian-born and native school children were recruited from a caravan-dwelling site and a boarding school and from a town adjacent to the caravan site and a boarding school, respectively.

Retinol concentration in maternal and cord serum: its relation to birth weight in healthy mother-infant pairs.

Background: Vitamin A is an essential micronutrient for the development and growth of the fetus. The objective of this study was to identify a possible association between low serum retinol and birth weight in healthy mother-infant pairs in Southern Israel. A secondary objective was to examine ethnic differences in maternal and cord serum retinol.

Establishment of immune competence in the avian GALT during the immediate post-hatch period.

Population dynamics of intestinal lymphocytes and the temporal development of lymphocyte functions were studied in broiler chicks during the first 2 weeks post-hatch. This period is of major immunological importance as the chick is immediately exposed to environmental antigens and pathogens. We show that the gut-associated lymphoid tissue contains functionally immature T and B lymphocytes at hatch, and that function is attained during the first 2 weeks of life as demonstrated by mRNA expression of both ChIL-2 and ChIFNgamma.

Effect of polyunsaturated fatty acid supplementation on biophysical parameters and chilling sensitivity of ewe oocytes.

Fat supplementation in the diet influences reproductive performance of lactating ruminants. Changes in the fat supply alter fatty acid composition and this can affect physical properties of cell membranes. This study examined the effect of rumen bypass polyunsaturated fatty acid (PUFA) supplementation on oocyte quality, chilling sensitivity, and lipid phase transition in oocytes of the sheep.