Lupins and energy-yielding nutrients in ewes. II. Responses in ovulation rate in ewes to increased availability of glucose, acetate and amino acids

Abstract

An experiment, using a total of 320 Merino ewes, over two successive breeding seasons was conducted to investigate the separate effects of energy-yielding and protein-yielding nutrients on ovulation rate in sheep. The available energy-yielding or protein-yielding nutrients in the blood of sheep fed a maintenance pelleted ration were increased by either intravenous infusions of metabolites (acetate, glucose or acetate + glucose), feeding lupin grain, modification of the pattern of rumen fermentation to increase propionate production using the ionophore, lasalocid, or by feeding of ruminally undegradable protein (formaldehyde-treated casein). All treatments were given for 9 days prior to and including expected time of ovulation. Ovulation rates were measured by laparoscopy. In the first season (the 1984 experiment) when the effects of lupin grain, glucose + acetate and formaldehyde-treated casein were compared, ovulation rates were increased significantly in the group fed lupin (29%, P less than 0.001) and the group infused with glucose + acetate (24%, P less than 0.01). There was an apparent (17%) but statistically non-significant increase in the group fed casein. In comparisons between lupin grain, glucose, acetate, glucose + acetate, formaldehyde-treated casein and lasalocid in the 1985 experiment there were similar significant increases in ovulation rates in the groups fed lupin, and those infused with glucose or glucose + acetate (approximately 25%, P less than 0.001). The increase in the group infused with acetate was lower at 14% (P less than 0.05) and the increases of 7% in the groups fed casein or lasalocid were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adiponectin and resistin: potential metabolic signals affecting hypothalamo-pituitary gonadal axis in females and males of different species

“…For example, in cattle selected for high milk production, high negative energy balance in the post-partum period is associated with reduced fertility (Wathes et al 2007). In sheep, it is well known that an increase in availability of energy substrates is associated with an increase in prolificacy (Teleni et al 1989). In pigs, it is also known that a negative energy balance and a decrease in body fat results in a reduction in litter size and viability of piglets (Quesnel et al 2007).…”

Glucogenic supply increases ovulation rate by modifying follicle recruitment and subsequent development of preovulatory follicles without effects on ghrelin secretion

“…In brief, a supplementation for 4-6 days around timing of preovulatory follicle selection increases the ovulation rate over 20-30%, without changes in body weight (Scaramuzzi et al 2006). This effect, termed 'immediate nutrient effect' or 'acute effect', was firstly described to be obtained by supplementing with lupin grains ('lupin effect'; Stewart & Oldham 1986, Teleni et al 1989. Thereafter, numerous studies have reported the positive energy balance of short-term nutritional protocols with energy-yielding nutrients, such as lupin grain (Rowe & Ferguson 1986, Smith & Stewart 1990, Pearse et al 1994, Williams et al 2001, Munoz-Gutierrez et al 2002, corn grain (Landau et al 1995, Letelier et al 2008, infusion of nutrients, like amino acids and glucose (Teleni et al 1989, Downing et al 1995, Landau et al 1996, Rodríguez-Iglesias et al 1996, Rubio et al 1997, Munoz-Gutierrez et al 2002 and metabolic hormones (insulin; Hinch & Roelofs 1986).…”

The influence of processing corn grain on glucose metabolism in ewes

“…In addition to its being a precursor of 85% of the lactose exported in milk (Annison and Linzell, 1964), glucose has been shown to be involved in determining ovulation rate (Teleni et al, 1989). Glucose is the main substrate for provision of energy to the uterus and fetuses (Wolff and Meschia, 1982).…”