Previous studies have suggested that luminal polyamines can directly influence intestinal differentiation of neonatal rats. The present investigation has demonstrated the presence of high levels of polyamines in porcine milk and in the intestinal tissues of suckling pigs. The quantities of polyamines in sow's milk sampled between wk 1 and 8 of lactation were determined using high performance liquid chromatography (HPLC). The concentration of milk spermidine (SPD) remained constant over the first 3 to 4 wk of lactation but increased 4-fold between wk 4 and 7. Neither putrescine nor spermine (SPN) were detected in any of the milk samples. During intestinal development the mucosal SPD/SPN ratio was elevated between wk 1 and 3 and wk 5 and 7. The latter period of increase corresponded with the surge in milk SPD concentration. It is suggested that milk SPD is taken up from the intestinal lumen and is involved in potentiating intestinal differentiation during the latter part of the suckling period.
The factor(s) produced by porcine cumulus cells (cumulus cell factor (s): CCF) was described as quantitatively inhibiting the maturation of oocytes in vitro (Petr et al, 1989). When 1, 10, 20 or 40 cumulus oocyte complexes (COCs) were cultured in a droplet of medium (vol 10 microliters), germinal vesicle breakdown (GVBD) was observed in 85, 78, 57 or 19% of the oocytes, respectively. GVBD was observed in 82, 84, 80 or 90% of cumulus-free oocytes, respectively, when they were cultured at the same numbers per 10-microliters droplet. When 1, 10, 20 or 40 cumulus-free oocytes were cultured under the same conditions in a medium containing 140 dbcAMP per ml, 61, 63, 60 or 58% of them were observed at GVBD. However, when COCs were cultured in a 10 microliter droplet of medium with 140 micrograms of dbcAMP per ml, GVBD occurred in 64, 42, 9 or 0% respectively. Based on these results, we can conclude that dbcAMP exerted a further inhibitory effect on GVBD in pig oocytes cultured under the influence of inhibitory factor(s) from cumulus cells. On the other hand, dbcAMP was shown to partly overcome the effect of CCF on GVBD in porcine oocytes. This suggestion was based on the finding that a 6-h pre-culture of COCs in a medium with 1,000 micrograms of dbcAMP significantly decreased the subsequent effect of CCF (GVBD: 44%) compared with those pre-cultured in a medium with 140 micrograms of dbcAMP/ml (GVBD:5%) or without dbcAMP (GVBD: 15%).(ABSTRACT TRUNCATED AT 250 WORDS)
A new artificial nutritive medium has been developed for the axenic culture of Artemia enabling the production of adults in less than 1 wk. The techniques for its preparation have been detailed. Its utilization is recommended for the standardized production of experimental animals.
The role played by membrane lipid environment on cardiac function remains poorly defined. The polyunsaturated fatty acid profile of myocardial phospholipids could be of utmost importance in the regulation of key-enzyme activities. This study was undertaken to determine whether selective incorporation of n-6 or n-3 fatty acids in membrane phospholipids might influence cardiac mechanical performances and metabolism. For 8 wk, male weaning Wistar rats were fed a semi-purified diet containing either 10% sunflower seed oil (72% C18:2 n-6) or 10% linseed oil (54% C18:3 n-3) as the sole source of lipids. The hearts were then removed and perfused according to working mode with a Krebs-Henseleit buffer containing glucose (11 mM) and insulin (10 Ul/l). Cardiac rate, coronary and aortic flows and ejection fraction were monitored after 30 min of perfusion. Myocardial metabolism was estimated by evaluating the intracellular fate of 1-14C palmitate. Sunflower seed oil and linseed oil feeding did not modify either coronary or aortic flow, which suggests that cardiac mechanical work was not affected by the diets. Conversely, cardiac rate was significantly decreased (-18%; P less than 0.01) when rats were fed the n-3 polyunsaturated fatty acid rich diet. Radioanalysis of the myocardial metabolism suggested that replacing n-6 polyunsaturated fatty acids by n-3 polyunsaturated fatty acids: i) did not alter palmitate uptake; ii) prolonged palmitate incorporation into cardiac triglycerides; iii) reduced beta-oxidation of palmitic acid. These results support the assumption that dietary fatty acids, particularly n-6 and n-3 fatty acids, play an important role in the regulation of cardiac mechanical and metabolic activity.
The aim of this study was to compare the growth hormone (GH) receptor in liver microsomal fractions of normal chickens (Dw) and chickens carrying the dwarf gene (dw). Specific binding of GH to its hepatic receptor was significantly higher for Dw embryos from d 14 till d 20 of incubation than for dw embryos. The difference in binding was due to a decreased binding capacity but not affinity in the livers of the dwarf embryos. The same binding pattern was found in livers of adult chickens: lower binding was again caused by a lower number of GH receptors and at this stage the difference was even clearer than during embryonic development. Binding studies on livers of growing chicks demonstrated that binding was low for both genotypes, but a small though significant difference between them remained. The cause of this decrease in number of GH receptors in dwarf birds has yet to be determined but may be due to the primary action of the dwarf gene.
The in situ starch degradation of 5 feeds (barley, maize, pea, oats and wheat bran) has been measured (trial 1), and the influence of particle size on starch degradation investigated with 3 feeds (barley, maize, pea) (trial 2). The starch degradability of barley, oats and wheat bran was found to be higher than that of pea, and higher again than that of maize: 98, 97, 96, 90 and 58% respectively. For barley, oats and wheat bran, starch was degraded more rapidly than the other dry matter (pm) components. Maize and pea starches were degraded at the same rate as non-starchy components. The particle size variations between feeds ground on the same screen may partly explain variations in starch degradability. When the particle size increased from 0.8 to 6.0 mm screen grinding, in situ starch degradability decreased; the decrease was higher for maize (13.8 points) than for barley (7.4 points) or pea (10.4 points).
The importance of olfactory cues in inducing luteinizing hormone and testosterone secretion as a response to stimulation by sexually receptive ewes has been tested. In sexually experienced rams, olfactory stimulation with urine, wool and vaginal secretions from sexually receptive females placed in a mask did not induce an endocrine response. The female-induced secretion of LH and testosterone was similar in anosmic, sham-operated and in control rams. These results show that olfactory cues are not necessary in the mediation of interindividual stimulation of endocrine response in the sexually experienced ram.
Les acides gras saturés longs (AGSL) sont considérés comme responsables d'hyperagrégabilité plaquettaire (Renaud et Mac Grégor, 1980) phénomène qui pourrait être lié à la présence, dans les lipides plasmatiques, d'acide ei- cosatriénoïque (C20:3, n-9) (Lagarde et al, 1983; Davenas et al, 1984) marqueur de ca- rence en acides gras essentiels.Nous avons
The purpose of this study was to determine whether the presence of bacterial endotoxin in the bovine serum albumin (BSA) used to supplement media utilized for sperm preparation and co-culture of bovine sperm and oocytes affects in vitro penetration and embryonic development of oocytes matured in vitro. The chromogenic limulus amoebocyte lysate (LAL) test was used for quantification of the content of endotoxin. The proportion of penetrated ova was significantly greater (P greater than 0.0005) for the endotoxin-contaminated group (89%) versus the non-contaminated group (61%), but this was probably not due to endotoxin contamination. The presence of endotoxin resulted in a high rate of polyspermy (27% versus 4%, respectively; P greater than 0.0005), while the occurrence of parthenogenetic activation was the same for each group (8%). The proportion of total embryos put into culture that developed to the blastocyst stage by day 8 was similar (30% and 26%) for the contaminated and non-contaminated group, respectively. Fifty-three and 69%, respectively, hatched on day 10. These results suggest that endotoxin induces polyspermy, but has no adverse effect on embryonic development.
In vitro maturation and fertilization of cattle oocytes and subsequent in vitro culture of zygotes and embryos is discussed in the context of recent encouraging data. Mass production of embryos produced in this way in the future will have a great impact on animal production and animal breeding plans, for example the so-called MO-ET (multiple ovulation and embryo transfer) plan which aims at establishing nucleus breeding herds.
L’évacuation gastrique de l’azote total et de l’azote protéique est plus rapide avec les aliments LN et LD qu’avec l’aliment témoin : rapportée à la quantité d’azote total ingéré, les quantités collectées en 6 h sont respectivement équivalentes à 97, 100 et 59% pour l’azote total et à 72, 78 et 35% pour l’azote des culots. Par contre, les quantités d’azote non protéique (surnageants) sont voisines avec les 3 aliments : 26, 26 et 24%. La composition en acides aminés des surnageants est plus proche de celle du CMP avec les aliments LN et LD qu’avec l’aliment témoin pendant la première h. Par la suite, elle se rapproche de plus en plus de la composition du lait avec les aliments LN et LD et de la
