Effect of cyclodextrin-encapsulated beta-carotene on progesterone production by bovine luteal cells

Carotenoids in female and male reproduction

Carotenoids are among the best-known pigments in nature, confer color to plants and animals, and are mainly derived from photosynthetic bacteria, fungi, algae, plants. Mammals cannot synthesize carotenoids. Carotenoids' source is only alimentary and after their assumption, they are mainly converted in retinal, retinol and retinoic acid, collectively known also as pro-vitamins and vitamin A, which play an essential role in tissue growth and regulate different aspects of the reproductive functions. However, their mechanisms of action and potential therapeutic effects are still unclear. This review aims to clarify the role of carotenoids in the male and female reproductive functions in species of veterinary interest. In female, carotenoids and their derivatives regulate not only folliculogenesis and oogenesis but also steroidogenesis. Moreover, they improve fertility by decreasing the risk of embryonic mortality. In male, retinol and retinoic acids activate molecular pathways related to spermatogenesis. Deficiencies of these vitamins have been correlated with degeneration of testis parenchyma with consequent absence of the mature sperm. Carotenoids have also been considered anti-antioxidants as they ameliorate the effect of free radicals. The mechanisms of action seem to be exerted by activating Kit and Stra8 pathways in both female and male. In conclusion, carotenoids have potentially beneficial effects for ameliorating ovarian and testes function.

Valorizing okara waste into nutritionally rich polysaccharide/protein-extracts for co-encapsulation of β-carotene and ferrous sulphate as a potential approach to tackle micronutrient malnutrition

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Okara was upcycled into encapsulation materials using microwave assisted technique.

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Okara and zein as excipient used as encapsulation substrate for micronutrients.

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The formulation produced desirable sequential release of micronutrients in SGF and SIF.

Colossal amounts of food waste are generated and discarded daily at the expense of financial resources and at a detriment to the environment. One such food waste, okara – a soybean by-product, is valorized in this study by upcycling it into nutritional extracts for micronutrients encapsulation. Micronutrient malnutrition, particularly in the developing world, is a major public health challenge. Herein, okara extracts were obtained through a low-cost extraction process and was subsequently developed as an encapsulant material for micronutrients β-carotene, and ferrous sulphate encapsulation, using zein as an excipient. Spray-drying, as a scalable technique, was employed to produce various formulations which were assessed for release profiles, shelf-life, β-carotene antioxidant activity and cell cytotoxicity. Finally, an optimized dual-micronutrient formulation displayed a sequential release with ferrous sulphate releasing in simulated gastric fluid, and β-carotene releasing predominantly in simulated intestinal fluid. This sequential release profile favors the absorption of both the micronutrients and could potentially enhance their bioavailability.

Effect of two postpartum intramuscular treatments with β-carotene (Carofertin®) on the blood concentration of β-carotene and on the reproductive performance parameters of dairy cows

The aim of the study was to determine whether two postpartum intramuscular treatments with 200 mg of beta-(β-)carotene (Carofertin; Alvetra u. Werfft, Vienna, Austria) in a 14-day interval increases β-carotene concentrations in blood, particularly around the time of the first artificial insemination (AI), and to test the effect of the treatment on fertility parameters, luteal size, and progesterone blood levels of dairy cows. A total of 297 Holstein dairy cows were enrolled in the study. Between 28 and 34 days postpartum (dpp) β-carotene concentrations were measured in blood samples using an on-site test (iCheck carotene; BioAnalyt, Teltow, Germany). Cows with a β-carotene concentration <3.5 mg/L, indicating a deficiency of β-carotene, were allocated either to the β-carotene treatment group BCT (n = 123) or to the control group CON (n = 121). Cows with concentrations ≥3.5 mg/L were assigned to an optimally supplied reference group (REF; n = 53). Cows in the BCT group received 200 mg of β-carotene intramuscularly at 28-34 dpp and at 42-48 dpp. Further blood samples were collected at 35-41 dpp, 42-48 dpp, 49-55 dpp, and in the week after the first AI and their β-carotene concentrations were analyzed. Between day 10 and 14 after the first AI, the blood progesterone concentration was measured and the size of the corpus luteum (CL) was determined by ultrasound. Blood β-carotene concentrations increased in the BCT cows in the week after the treatment with a peak at 49-55 dpp and were significantly higher than in the CON group at each time point after the first treatment. Logistic regression models, however, revealed that the treatment with β-carotene had no effect on first service conception rate, days to first service, time to pregnancy, or percentage of pregnant cows within 150 dpp. Furthermore, there was no effect on progesterone concentration or the size of the CL between the groups. In conclusion, two treatments with Carofertin postpartum increased β-carotene blood concentrations but had no effect on the fertility parameters in this study.

Effects of mancozeb, metalaxyl and tebuconazole on steroid production by bovine luteal cells in vitro

Mancozeb, metalaxyl and tebucanazole are widely used pesticides in agriculture and industry to treat plant pathogenic fungi. Livestock may be exposed to such substances by consuming contaminated plants. The present study was designed to evaluate the effects of these three fungicides on bovine luteal cell steroidogenesis. Luteal slices from mid-cycle corpus luteum were dissociated into single cell suspension in aerated (O₂) culture media (DMEM/F12) by enzymatic digestion. The cells were incubated in newborn calf serum (10%) for 18 h and then with serum-free media containing mancozeb (0.01 μM, 0.1 μM, 1 μM), tebuconazole (1 μM, 10 μM, 100 μM) or metalaxyl (100 μM, 500 μM, 2500 μM) for additional 96 h. The medium was replaced on day 1 and 3; and the retrieved medium was stored at -20 °C until progesterone assay. Treatment of cells with three different fungicides induced dose dependent variable decrease in steroid synthesis during incubation periods. Incubation of cells with 1 μM mancozeb exhibited a 33% decline in steroid synthesis on day 3 and 48% decline on day 5 compared with controls. Treatment of cells with 100 μM tebuconazole and 500 μM metalaxyl resulted in a 65% and 31% decrease, respectively, in progesterone accumulation on day 5 of incubation. Fungicide induced suppressive effects on luteal steroidogenesis were as metalaxyl < tebuconazole < mancozeb. Results of the present study suggest that designated concentrations of all three fungicides studied might have varying degrees of adverse effects on luteal steroidogenesis.

Size distribution of steroidogenic and non-steroidogenic ovine luteal cells throughout pregnancy

The present study examines the size distribution of ovine steroidogenic and non-steroidogenic luteal cells throughout pregnancy. Cells were isolated from corpora lutea collected from early (< 8 weeks), mid (9 to 14 weeks) or late (15 to 18 weeks) stages of pregnancy. Cells were stained for 3β-hydroxysteroid dehydrogenase (3β-HSD) activity, a marker for steroidogenic cells. Both 3β-HSD positive and β-HSD negative cells covered a wide spectrum of size ranging from 7 to 37 μm in diameter. There was a significant increase (P > 0·01) in mean diameter of non-steroidogenic luteal cells as pregnancy progressed. Mean diameter of 3β-HSD negative cells increased from 17·8 (s.e. 0·4) μm in the corpus luteum of early stage of pregnancy to 22·4 (s.e. 0·3) μm in the corpus luteum of advanced pregnancy. However, there was no significant increase in the mean diameter of 3β-HSD positive cells. Corpora lutea obtained from early stages of the pregnancy contained more steroidogenic cells than the cells obtained from mid and late pregnancy (P < 0·01). Percentage of 3β-HSD negative cells had increased 2·07-fold by 18 weeks of pregnancy when compared with the early stage of pregnancy. In contrast, percentage of 3β-HSD positive cells had decreased to 50% of starting values during the same period (P < 0·05). These results indicate that the ovine corpus luteum of pregnancy is morphologically dynamic over the course of pregnancy. Steroidogenic activity of luteal cells may decrease as pregnancy progresses, especially activity of the large luteal cells.

Effects of cholesterol and cAMP on progesterone production in cultured luteal cells isolated from pseudopregnant cat ovaries

The present study was designed to incubate luteal cells isolated from pseudopregnant cats and to investigate the effects of cholesterol and cAMP on luteal progesterone production. Corpora lutea were collected from the cats on days 10 and 15 of pseudopregnancy. Luteal cells were isolated from the ovaries by collagenase digestion. Steroidogenic luteal cells were stained for 3beta-hydroxysteroid dehydrogenase (3beta-HSD) activity. Cells (2 x 10(4)) staining positive for 3beta-HSD were cultured for up to 7 days. The cells were treated with 22(R)-hydroxycholesterol (22R-HC) and dibutyryl cyclic AMP (dbcAMP) on days 1, 3 and 7. Treatment of cells with 22R-HC resulted in a dose-dependent increase (p<0.001) in progesterone production. When 22R-HC was used at a concentration of 10 microg/ml, it resulted in 2.7- and 5.1-fold increases in progesterone production on days 3 and 5, respectively. When the dose was doubled (20 microg/ml), treated cells produced four times more progesterone on days 3 and 7, and three times more on day 5. By day 7, progesterone production increased up to 9.1 times more than the control. Incubation of cells with both concentrations of dbcAMP (0.1 mM and 1 mM) resulted in significant stimulations of progesterone on days 5 and 7 (p<0.001). However, on day 3, only higher doses of dbcAMP (1 mM) resulted in significant stimulation (p<0.05). Progesterone production was increased up to 2- and 2.9-fold of the control when cells were treated with lower concentration of dbcAMP (0.1 mM) on days 5 and 7, respectively. Incubation of cells with 1 mM concentrations of dbcAMP induced a 3.2-fold increase on day 5 and a 5-fold increase on day 7. In conclusion, a successful incubation was performed for long-life culturing of luteal cells collected from pseudopregnant cats. The method works well and allows for optimal growth and development of cells in the culture. The present study also demonstrated that incubating cat luteal cells with 22R-HC and dbcAMP induces a significant increase in luteal progesterone synthesis.