Effect of dietary beta-carotene on the early embryonic development and uterine fluid composition of gilts

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.

Association of concentrations of beta-carotene in plasma on pregnancy per artificial insemination and pregnancy loss in lactating Holstein cows

The objective of this study was to determine the association of beta-carotene concentration in plasma at the moment of artificial insemination (AI) on pregnancy/AI in lactating Holstein cows. A total of 399 events from 364 lactating Holstein cows were enrolled in the trial (143 primiparous and 221 multiparous). All cows were assigned to a timed AI protocol based on estradiol and progesterone. Blood samples were collected at the moment of AI and at 24 and 31d post-AI (samples on 31 d post-AI were collected only from cows that were diagnosed pregnant). The BCS were recorded at the time of AI. Plasma beta-carotene was quantified from blood samples taken at the time of AI using a single step denaturation and extraction into a solvent, followed by measurement using a portable spectrophotometer. Pregnancy-associated glycoproteins (PAG) were analyzed in blood samples taken at 24 and 31 d post-AI of pregnant cows. Milk production was collected for the entire experimental period. Pregnancy diagnosis was performed by ultrasound 31 and 60 d post-AI. Data was analyzed using the MIXED and GLIMMIX procedures of SAS. Cows classified as thin (<2.75) tended to have lower concentration of beta-carotene at AI when compared with those classified as Moderate (≥3.00; 3.8 ± 0.1 vs. 4.3 ± 0.1 μg/mL; P = 0.09). Concentration of beta-carotene were greater in multiparous compared with primiparous (P < 0.01). There was no correlation between concentration of beta-carotene and milk production (r = 0.04; P = 0.10). When plasma beta-carotene was categorized in quartiles, cows in the 1st quartile had lower pregnancy/AI and higher pregnancy losses when compared with cows that were in the 2nd, 3rd and 4th quartile (pregnancy/AI = 19.2 ± 4.5, 33.7 ± 4.7, 36.9 ± 5.0 and 39.8 ± 5.4%, respectively; P = 0.05; pregnancy losses = 41.9 ± 4.8, 20.4 ± 3.7, 22.1 ± 4.1, and 15.7 ± 4.2%, respectively; P < 0.05). There was no association between concentrations of beta-carotene at AI and PAG at 24 d post-AI (P = 0.60). Cows with greater concentrations of beta-carotene at AI were more likely to have greater concentrations of PAG at 31 d post-AI (P < 0.01). In conclusion, the concentration of beta-carotene at AI was affected by BCS and parity. Cows with higher concentrations of plasma beta-carotene at AI had greater pregnancy/AI, lower pregnancy losses and greater concentrations of PAG at d 31 post-AI, suggesting it may be associated with placental function in lactating dairy cows.

The effect of dietary alfalfa meal on the chicken meat quality

The purpose of this study was to investigate the effect of feed mixtures with proportion of alflafa meal 4% on body weight of broiler chickens, fat content their meat and oxidative stability meat fat under storage conditions. Final hybrid Cobb 500 chickens were used in the experiment. The broiler chickens were fed with feed mixtures starter from the 1st to the 18th day, grower from the 19th to the 31st day and finisher from the 32nd to the 38th ad libitum. An alfalfa meal of 4% was added in the feed mixtures of experimental group. In our experiment, we used alfalfa meal, which was made from Medicago sativa L. harvested in the bud's phase. The carcasses of broilers were stored at -18° C for a period of nine months. The average weight of chickens at the end of our experiment, the control group was 1685.6 g. In experimental group with addition of 4% alfalfa meal in feed mixtures, the chickens weighed 1709.6 g. The difference in body weight between the groups was not statistically significant (p >0.05). The average fat content in chicken meat was lower in the group with a share of 4% alfalfa meal 2.33 g.100g-1 compared to the fat content in meat chickens control group 2.59 g.100g-1. Differences in fat content in meat between the groups were not statistically significant (p >0.05). In our experiment, the average peroxide value of fat in meat under storage conditions 9 months at -18°C was lower in the group with a share of 4% alfalfa meal 2.42 µmol O2.g-1 compared with an average value of peroxide number 5.79 µmol O2.g-1 in the control group. Medicago sativa L. is an interesting object for research. It is characterized by high content of protein and biologically active substances that are effective for the promotion of health, and also an improvement the nutritional value and technological properties of the poultry food, when is used in feed mixtures.

Short-term beta-carotene-supplementation positively affects ovarian activity and serum insulin concentrations in a goat model

In early October 2010, adult goats (no.=22, 3.5 yr old, 7/8 Sannen-Alpine, 26° N, 103° W, at 1117 m), were randomly assigned to: i) beta-carotene group (BC) [no.=10; live weight (LW)=45.9±1.97 kg, body condition score (BCS) =3.04±0.08; orally supplemented with 50 mg of BC per goat per day]; ii) control group (CONT) (no.=12; LW=46.2±2.04 kg, BCS=3.0±0.08). Animals received a basal diet of alfalfa hay, corn silage, and corn grain, having free access to water, shade, and mineral salts. During the second half of October, estrus was synchronized by using intravaginal sponges. Thereafter, by mid-follicular phase, an intensive blood sampling (6 h × 60 min) was performed to evaluate serum insulin concentrations (INS) by radioimmunoassay. By the end of the luteal phase, an ultrasonographic scanning was performed to evaluate total ovarian activity (TOA) [TOA=total follicles (TF) + total corpus luteum (TCL)]. The whole experimental period consisted of 34 days pre- and 17 days post-ovulation, for a total of 52 days. Average LW and BCS did not differ (p>0.05) during the experimental period. Nonetheless, increases in TF no. (5.0 vs 3.4±0.6 units; p=0.05), TCL no. (3.4 vs 2.8±0.2 units; p=0.05), TOA (8.1 vs 6.2±0.6 units; p=0.05) and INS (4.6 vs 3.9±0.4 ng ml-1; p=0.05) favored to the BC-supplemented group. A positive correlation between LW (r(2)=0.42; p=0.04) and BCS (r(2)=0.47; p=0.02) with respect to ovulation rate, was detected. BC-supplementation increased ovarian activity in the female goat while positively affected the release pattern of insulin, suggesting a potential role of BC as a central and/or pancreas-activating molecule in adult goats; such results may hold not only physiologic but also clinical significance.

Betacarotene supplementation increases ovulation rate without an increment in LH secretion in cyclic goats

This study aimed to evaluate the effects of betacarotene (BC) supplementation on ovulation rate (OR) and luteinizing hormone (LH) secretion in adult goats during the breeding season. Additionally, total ovarian activity (TOA) comprising the total number of ultrasonographically detectable antral follicles (AF) and corpora lutea (OR) was also assessed. In early October, adult goats [n=22, 3.5 years of age, 7/8 Sannen-Alpine; 26°N, 103°W at 1117m.a.s.l.] were randomly assigned to: (i) BC group (BCG), orally supplemented with 50mg of BC/goat/day [n=10; live weight (LW)=45.9±2.0kg, body condition score (BCS; range: 0-emaciated to 5-obese)=3.0±0.1], and (ii) control group (CONT) [n=12; LW=46.2±2.0kg, BCS=3.0±0.1]. All animals received a basal diet of alfalfa hay, corn silage and corn grain, with free access to water and mineral salts. The whole experimental period spanned 34 days before and 17 days after ovulation. On day 23 of the experiment, estrus was synchronized with progestin-releasing intravaginal sponges; 36h prior to estrus, an intensive blood sampling (every 15min for 6h) was performed to determine mean LH concentrations, pulsatility (LH-PULSE) and area under the curve (LH-AUC) for serial LH concentrations. Afterwards, by the end of the luteal phase (i.e., 17 days after the onset of estrus), an ultrasonographic scanning was performed to evaluate OR and TOA [AF+OR]. The average LW and BCS did not differ (p>0.05) during the experimental period. BC-supplemented goats showed an increase in OR (3.4±0.2 versus 2.8±0.2; p<0.05) and exhibited lower (p<0.05) serum LH concentrations, LH-AUC and LH-PULSE compared to CONT. A positive correlation was recorded between OR and LW (r(2)=0.42, p<0.05) and BCS (r(2)=0.47, p<0.05). In addition, AF (5.0±0.6 versus 3.4±0.6) and TOA (8.4±0.6 versus 6.2±0.6) were greater (p<0.05) in the BC-supplemented group than CONT. Supplementation with BC enhanced ovarian follicular development and ovulation rate in adult female goats under decreased photoperiods through LHRH-independant pathways or direct effects of BC on ovarian function.

Long-term betacarotene-supplementation enhances serum insulin concentrations without effect on the onset of puberty in the female goat

The effect of betacarotene (BC) supplementation on the onset of puberty and serum insulin levels in goats was evaluated in the study. In June, prepuberal goats (n=17; 3 months old; 7/8 Saanen-Alpine; 26° NL) were randomly assigned to one of two groups: 1/ betacarotene group supplemented daily with 50 mg of BC (n=9; live weight [LW]: 17.3±1.0 kg; body condition score [BCS]: 3.34±0.12) or 2/ control group (CONT; n=8; LW:16.1±1.0 kg; BCS=3.17±0.12). From June to November, an intermittent blood sampling was performed twice per week in both groups to evaluate serum progesterone (P(4)), while monthly samples were intended for insulin (INS) determination. Initial mean LW (16.7±1.0 kg) and BCS (3.31±0.12) were similar (p>0.05) in both groups. Mean serum insulin (1.37 vs. 1.18±0.09 ng/ml), age of puberty (215.7 vs. 226.5±6.6 days) and the percentage of goats reaching puberty (44.4 vs. 25.0±17.0%) did not differ (p>0.05) between BC and CONT group, respectively. However, increase in serum insulin during the second half of the experiment was observed in BC group (p<0.05) which was positively correlated with LW (r=0.95; p<0.05). In addition, as LW (r=-0.89) and serum insulin (r=-0.76) levels increased, the natural photoperiod decreased, revealing negative correlations (p<0.05) between the respective variables. In this study, BC supplementation did not promote precocious puberty and did not affect the percentage of goats reaching activation of the hypothalamic-hypophyseal-gonadal axis during the establishment of puberty. Nonetheless, BC supplementation positively affected the release pattern of insulin suggesting a potential role of BC as pancreas-activating molecule.

Short-term intake of beta-carotene-supplemented diets enhances ovarian function and progesterone synthesis in goats

The effect of beta-carotene supplementation upon luteal activity, measured as number (CLT) and volume (VLT) of corpus luteum, and P4 synthesis in goats, was evaluated. Goats (n = 22, 34 months) were randomly assigned to one of two experimental groups: (i) beta-carotene [Beta, n = 10; body weight (BW = 44.8 +/- 1.45 kg), body condition score (BCS = 3.25 +/- 0.07)], and (ii) Control (Control, n = 12; BW = 45.30 +/- 1.32 kg, BCS = 3.33 +/- 0.06). Upon oestrus synchronization, the Beta group received 50 mg of beta-carotene per day during 35 days pre- and 17 days post-ovulation. The day 4, 8, 12 and 16 post-ovulation, blood samples were collected for quantification of serum P4 concentrations by radioimmmunoassay, and transrectal ultrasonographic scanning was performed at day 18 for evaluating CLT and VLT. Overall, CLT and VLT mean were 3.10 and 2211.1 mm(3) respectively. The Beta-goats depicted both the largest values for CLT (p = 0.07) and serum P4 levels (p = 0.05), with no differences (p = 0.53) for VLT between treatments. Results suggest a higher efficiency within the cellular-enzymatic groups defining the steroidogenic pathways in the beta-carotene-supplemented goats, generating a larger P4 synthesis. The last is essential for ovulation of healthy oocytes, maintenance of uterine quiescence, nourishment and survival of the embryo around implantation; all of them of paramount significance during the maternal recognition of pregnancy process.