A B S T R A C r To evaluate gonadotropin release in polycystic ovary syndrome (PCO), one or more of the following hypothalamic-pituitary function tests were performed on 24 patients with the syndrome. These tests included (a) the pulsatile pattern and day-to-day fluctuation of gonadotropin release; (b) effects of exogenous estrogen and antiestrogen (clomiphene) administration on gonadotropin release; and (c) pituitary responsiveness to maximal (150 i'g) and submaximal (10 Ag) luteinizing hormone-releasing factor (LRF) injections. In 10 of the 14 patients sampled frequently (15 min) for 6 h, luteinizing hormone (LH) levels were elevated above the concentration seen in normal cycling women (except the LH surge). These high LH concentrations appeared to be maintained by and temporally related to the presence of exaggerated pulsatile LH release, either in the form of enhanced amplitude or increased frequency. In all subjects, levels of folliclestimulating hormone (FSH) were low or low normal, and a pulsatile pattern was not discernible. In four patients, daily sampling revealed marked day-to-day fluctuation of LH but not FSH. That the elevated LH levels were not related to a defect in the negative-feedback effect of estrogen was suggested by the appropriate fall of LH in four patients given an acute intravenous infusion of 17fi-estradiol. This infusion had no effect on FSH levels. In addition, clomiphene elicited rises of both LH and FSH that were comparable to the ones observed in normal women given the same treatment. The clomiphene study also suggested that the positive-feedback mechanism of estrogen on LH release was intact when the preovulatory rises of 179-estradiol induced appropriate LH surges. The elevated LH levels appeared to be related to a heightened pituitary responsiveness to the LRF. This was found in the 11 and 2 patients given maximal (150 sg) and submaximal (10 /Ag) doses of LRF, respectively. The augmented pituitary sensitivity for LH release correlated with the basal levels of both estrone (P <0.025) and 17j8-estradiol (P < 0.02). The net increase in FSH was significantly greater (P < 0.001) in the PCO patients than the normal women with maximal doses of LRF. With the smaller dose study, none of the injections had a discernible effect on FSH concentrations in either subject. The disparity between LH and FSH secretion could be explained by the preferential inhibitory action of estrogen on FSH release, coupled with a relative insensitivity of FSH release.These data indicate that in these PCO patients the abnormalities of the hypothalamic-pituitary regulation of gonadotropin secretion was not an inherent defect but represented a functional derangement consequent to inappropriate estrogen feedback, which led to a vicious cycle of chronic anovulation and inappropriate gonadotropin secretion.

No abstract

Black soldier fly (BSF) larvae represent a promising alternative ingredient for animal feed. Post-production processing can, however, affect their quality. This project aimed to optimize larval killing by comparing the effects on the nutritional and microbiological quality of 10 methods, i.e., blanching (B = 40 s), desiccation (D = 60 °C, 30 min), freezing (F20 = −20 °C, 1 h; F40 = −40 °C, 1 h; N = liquid nitrogen, 40 s), high hydrostatic pressure (HHP = 3 min, 600 MPa), grinding (G = 2 min) and asphyxiation (CO2 = 120 h; N2 = 144 h; vacuum conditioning, V = 120 h). Some methods affected the pH (B, asphyxiation), total moisture (B, asphyxiation and D) and ash contents (B, p < 0.001). The lipid content (asphyxiation) and their oxidation levels (B, asphyxiation and D) were also affected (p < 0.001). Killing methods altered the larvae colour during freeze-drying and in the final product. Blanching appears to be the most appropriate strategy since it minimizes lipid oxidation (primary = 4.6 ± 0.7 mg cumen hydroperoxide (CHP) equivalents/kg; secondary = 1.0 ± 0.1 mg malondialdehyde/kg), reduces microbial contamination and initiates dehydration (water content = 78.1 ± 1.0%). We propose herein, an optimized protocol to kill BSF that meet the Canadian regulatory requirements of the insect production and processing industry.

No abstract

Experiments were undertaken to investigate the apparent digestibility coecient (ADC) of a range of macro-and micronutrients in rainbow trout using three external digestibility markers (chromic oxide, acid insoluble ash and titanium dioxide, alone or in combination), and three methods of faeces collection (modi®ed Guelph system, St-Pee system and abdominal massage; hereafter referred to as column', 'collect' and`strip', respectively). For each method of faeces collection, three replicate tanks of ®sh were acclimated for 5 days to a practical diet containing the external marker followed by 5 days of faeces collection. Both marker type and collection method signi®cantly in¯uenced ADC estimate in a similar manner for dry matter, protein, nitrogen-free extract, ash and energy. The ADC was consistently highest for the column and lowest for the strip methods of collection, and titanium dioxide gave higher ADCs vs. the other markers. Lipid ADC did not dier between the column and collect methods, but collection of faeces by the strip method gave lower ADCs, irrespective of marker type. In general, nutrient ADC was higher with the combined markers than when single markers were employed. The in¯uence of marker type and collection method was less clear for the individual minerals studied. KEY WORDS

No abstract

No abstract

No abstract