Uriel A Sod-Moriah

Chickens fed with biomass of the red microalga Porphyridium sp. have reduced blood cholesterol level and modified fatty acid composition in egg yolk.

The biomass of the red alga Porphyridium sp.constitutes a unique combination of soluble sulfatedpolysaccharide that accounts for about 70% of thealgal dry weight, and various polyunsaturatedfatty acids (PUFA) such as arachidonic andeicosapentaenoic acid (AA, 20:4 ω6 and EPA,20:5 ω3). In view of earlier results in ourlaboratory showing a reduction in serum cholesteroland triglyceride levels in rodents fed with red algalbiomass, we set out to examine the influence of algalbiomass as a feed additive on the metabolism ofchickens, with an emphasis on blood and eggcholesterol levels. For that purpose, lyophilizedalgal biomass was fed to 12–13, 30-week-old, WhiteLeghorn chickens for 10 days at a proportion of 5% or10% of the standard chicken diet. Twelve chickensfed with unsupplemented diet served as the control. No differences in body weight, egg number, and eggweight were found between the algal-fed chickens (atboth concentrations) and the control. However,chickens fed with algal biomass consumed 10% lessfood for both groups, and their serum cholesterollevels were significantly lower (by 11% and 28% forthe groups fed with 5% and 10% supplement,respectively) as compared with the respective valuesof the control group. Egg yolk of chickens fed withalgae tended to have reduced cholesterol levels (by10%) and increased linoleic acid and arachidonic acidlevels (by 29% and 24%, respectively). In addition,the color of the egg yolk was darker as a result ofthe higher carotenoid levels (2.4 fold higher) forchickens that fed with 5% supplement. Theseresults encourage the development of an improvedchicken feed having dietary fibers and polyunsaturatedfatty acids.

Soluble polysaccharide and biomass of red microalga Porphyridium sp. alter intestinal morphology and reduce serum cholesterol in rats

The present study investigated the effects of the red microalga Porphyridium sp. on gastrointestinal physiology and lipid metabolism in male Sprague-Dawley rats. Diets containing dietary fibre from pelleted red microalgal cells (biomass) or their sulfated polysaccharide, pectin or cellulose (control) were fed to rats for a period of 30 d. All three fibre-supplemented diets increased the length of both the small intestine and colon, with a significantly greater effect in rats fed the algal polysaccharide. The polysaccharide also increased mucosa and muscularis cross-sectional area of the jejunum, and caused hypertrophy in the muscularis layer. The algal biomass significantly lowered gastrointestinal transit time by 44% in comparison with the control rats. Serum and mucosal cholecystokinin levels were lower in rats on the pectin and polysaccharide diets, while cholecystokinin levels in rats fed algal biomass were not different from those in the control animals. In comparison with the control diet, all the experimental diets significantly lowered serum cholesterol levels (22-29%). Feeding of non-fermentable algal polysaccharide or biomass significantly increased faecal weight and bile acid excretion compared with pectin-fed or control rats. The algal polysaccharide and biomass were thus shown to be potent hypocholesterolaemic agents active at low concentrations in the diet. Both metabolic and morphological changes were observed following consumption of algae, suggesting several possible mechanisms by which the alga affects lipid metabolism. The results presented in the present study encourage the use of red microalga as a functional food.

Suppression and Recovery of Spermatogenesis in Dibromochloropropane Treated Rats

Unterdrückung und Erholung der Spermatogenese bei Dibromchloropropanbehandelten Ratten

Role of the Pineal Gland in Male Rats Chronically Exposed to Increased Temperature

The effects of the pineal gland on endocrine function (especially those of the gonads) were investigated in male rats chronically exposed to increased temperature. Weanling male rats were either pinealectomized (Px) or sham-operated (Sh). Following one week of recovery, animals were assigned to either control temperature of 21±1°C (PxC and ShC) or a temperature of 35±1°C (PxH and ShH). The animals were kept at their respective temperature for at least 30 days. In both groups (PxH and ShH) exposure to increased temperature resulted in a significant reduction in body and hypophysial weights, and in serum LH and testosterone levels as compared with the respective controls (PxC and ShC). Rectal temperature and serum corticosterone were also significantly increased. No changes were found in pineal hydroxyindole-O-methyltransferase activity of shamoperated rats kept in increased temperature (ShH vs. ShC). Pinealectomy alone (PxC vs. ShC) did not alter any of the measured parameters, except for increased pituitary LH content. Increased temperature plus pinealectomy (PxH vs. PxC; and PxH vs. ShH) caused a significant reduction in pituitary LH content and further accentuated (PxH vs. ShH) the diminished serum LH and testosterone levels evoked by exposure to high temperature. The results suggest that in male rats the pineal gland may play a role in moderating the changes in the reproductive processes that are induced by increased temperature.

Long Term Effects of Dibromochloropropane (DBCP) on Male Rats' Reproductive System

Summary: Adult male rats were injected s.c. once a week for 3 weeks with DBCP, 20 mg/kg B.W. Animals were sacrificed 5, 9, 13, 17, 25 and 50 weeks after last injection. Body weight was recorded once a week. Prior to sacrifice each male was presented with proestral females in order to determine the males mating behaviour and fertility. Testes were removed, weighed and taken for standard histological examination. DBCP treatment caused a reduction of body weight which reverted back to control levels some 17 weeks post injection. Testes weights were reduced and remained low despite the recovery of body weight. Generally, all males showed normal mating behaviour but most of them were infertile. Testicular histology showed a correlation between decreasing testicular weight and increasing percentage of degenerated seminiferous tubules, which was on the other hand correlated with decreasing tubular diameter. Serum levels of FSH and LH were significantly increased in the infertile DBCP treated males while values for the fertile ones were similar to those of controls. There were no differences in serum testosterone levels between DBCP treated and control animals. It is concluded that in DBCP treated rats testicular degenerative damages are associated with increased circulating gonadotrophin levels and with normal testosterone levels. Although mating behaviour is unaffected fertility is depressed and does not recover for at least 50 weeks post injection. It is suggested that DBCP treatment affects mainly the activity of the Sertoli cells while the Leydig cells are affected to a much lesser degree.

Tolerance to lipopolysaccharide is not related to the ability of the hypothalamus to produce prostaglandin E2

The effects of repeated administration of Escherichia coli lipopolysaccharide (LPS) on body temperature and hypothalamic prostaglandin E2 (PGE2) production was examined in male Sprague-Dawley rats to elucidate whether the development of endotoxin tolerance is related to the ability of the hypothalamus to produce PGE2. Initial injection of LPS resulted in hyperthermia, preceded by short-termed hypothermia, while no changes in body temperature were observed after the second injection (administered 48 h later). In contrast, LPS induced elevation in hypothalamic PGE2 production after both the first and second injections of the pyrogen. This led us to conclude that endotoxin tolerance is independent of the hypothalamic production of PGE2 in response to repeated administration of LPS.

Seasonal fluctuations in plasma testosterone levels and testes size in male goat (Capra hircus)-ibex (Capra ibex nubiana) crosses

Abstract 1. 1. Seasonal fluctuations in plasma testosterone levels and testes size were measured in two male goat ( Capra hircus )-ibex ( Capra ibex nubiana ) crosses ( goatex ) and in one male goat. 2. 2. In all animals, plasma testosterone levels peaked in August and testes sizes peaked in September–October. 3. 3. The fluctuations for all measurements were greater in the goatexes and thus it appears that these animals have greater variation in their reproduction capacities than the goat.

Effects of lipopolysaccharide on body temperature and plasma zinc and iron concentrations in rats exposed to different ambient temperatures

Abstract Lipopolysaccharide (LPS) induced biphasic changes in body temperature ( T b ) (initial hypothermia followed by hyperthermia) in male Sprague–Dawley rats kept at 22°C, and monophasic elevation in T b at 34°C. LPS decreased plasma zinc (Zn) or iron (Fe) concentrations, independently of heat-induced hyperthermia or LPS-induced changes in T b . Acute or chronic exposure of rats to high ambient temperature modifies their T b response to LPS, but not the effects of LPS on plasma Zn and Fe concentrations. It appears that the reduction of these elements in plasma could represent a common response to stress, including the response to endotoxin.

Testosterone modifies response to chronic heat exposure in rats

Eight weeks of heat exposure (34 +/- 0.5 degrees C) in sham-orchiectomized rats leads to an increase of body temperature, slowing of body growth rate, and decrease of serum corticosterone level, as compared with animals maintained at 21 +/- 2 degrees C. Orchiectomy decreases body temperature, slows growth rate, and increases plasma corticosterone concentration both in control and heat exposed animals. Testosterone administration reverts these parameters to initial values. We conclude that testosterone plays a role in the regulation of heat balance in male rats.

The Effect of Dibromochloropropane (DBCP) on In Vitro Cyclic AMP Levels and Testosterone Production in Rat Testes

Adult male rats were injected s.c. once a week for 3 weeks with DBCP, 20 mg/kg BW. Animals were sacrified 20 weeks after last injection. Body and testes weights were recorded and testes were taken for standard histological preparation and for in vitro experiments. The in vitro experiments were carried out on testes slices (90–110 mg) incubated for 3 h with or without the addition of hCG to the incubation medium. Cyclic AMP content of the tissue as well as testosterone released into the incubation medium were determined. Testes weights of DBCP treated animals were 68 % lower that that of controls. AU semiferous tubules were damaged and shrunken, thus, their number per microscope field was 2.6 times that of controls. Cyclic AMP levels in testes slices were similar in both DBCP treated and controls. The addition of hCG stimulated cyclic AMP accumulation to a much higher level in the DBCP treated than in controls. When calculated per one pair of testes the content in unstimulated pair was more than twice that of DBCP treated. Stimulation of hCG increased both DBCP treated and controls to similar levels. Testosterone release into the medium by slices was higher in DBCP treated than in controls and so was also the increment due to hCG stimulation. Similar results were obtained when testosterone release was calculated per one pair of testes.