Mammary gland leptin in relation to lactogenesis in the periparturient dairy goat

Serum insulin-like growth factor-1 and leptin concentrations in Black Bengal goats at different ages and gestation periods and their relationship to kid growth performance

Background and Aims

The impact of maternal hormone concentration on kid growth performance in relation to insulin-like growth factor 1 (IGF-1) and leptin is minimal. This study examined IGF-1 and leptin levels at varying ages and gestation periods for their correlation with Black Bengal goat kids' growth during the preweaning phase.

Materials and Methods

Blood samples were collected from 43 dams with different reproductive cycles and 28 prepubertal goats to measure serum concentrations of IGF-1 and leptin. Among dams, both hormones were investigated in different age ranges (<2, 2-3, 3-4, and >4 years old) and reproductive cycles (non-pregnancy, early gestation (1-50 days), mid-gestation (51-100 days), late gestation (101-135 days), and the last 15 days before delivery). After delivery, 65 kids from 34 dams were weighted weekly for 8 weeks to calculate average daily weight gain (ADG) at 0-4 weeks (ADG0-4 W) and 4-8 weeks (ADG4-8 W) and growth performance, including weight (W), height (H), length (L), chest girth (C) measured at birth (W0, H0, L0, and C0) and at 10 weeks of age (W10, H10, L10, and C10) were related to hormone serum concentrations in their dams at different gestation periods including the last 15 days before delivery.

Results

Dams had higher mean serum IGF-1 (p < 0.001) and leptin (p < 0.05) than prepubertal goats. Dams at late gestation had higher IGF-1 concentrations than those at early and mid-gestation and during the last 15 days before delivery. However, it was consistent with non-pregnant goats. The kid's growth performance correlated positively with IGF-1 concentration, which was collected in the last 15 days before delivery. Multivariate analysis showed that ADG0-4 W was higher in kids born from dams with high IGF-1 than those with low IGF-1 measured during the last 15 days of delivery, whereas leptin tended to have a similar effect.

Conclusion

Serum IGF-1 and leptin concentrations of dams measured during the last 15 days before delivery were associated with kid's growth during the preweaning period.

TRIENNIAL LACTATION SYMPOSIUM/BOLFA: Adipokines affect mammary growth and function in farm animals

The essential role of mammary fat pads in mammary growth and morphogenesis was the first indication that biologically active molecules, secreted from adipocytes or other stromal cells, could regulate endocrine cues for growth and function of the mammary gland. The presence of leptin and adiponectin receptors in mammary tissues suggested that locally produced or circulating adipokines could affect mammary growth and function. Herein, we present the current knowledge on the role of adipokines in mammary cell proliferation and differentiation and in lactogenesis and galactopoiesis in farm animals. We also address the role of milk adipokines in the neonate. Accumulating evidence suggests that adipokines could act as metabolic sensors, regulating mammary growth and function in periods of metabolic adaptations such as late pregnancy and early lactation. Indeed, different experiments reported that adiponectin and leptin expression varies according to physiological stages and nutritional status of the animal. The current review also demonstrates that adipokines, such as leptin and adiponectin, are important regulators of the action of lactogenic hormones in the mammary gland. Findings also suggest important roles for adipokines in growth and intestinal maturation of the neonate.

Peripartum changes in orexigenic and anorexigenic hormones in relation to back fat thickness and feeding strategy of sows

Highly prolific sows often experience peripartum hypophagia, resulting in decreased production rate. Leptin, ghrelin, and resistin are known as feed intake-regulating hormones in many species, but it is yet unknown how feeding strategy and body condition will affect these hormones around parturition in sows. In the present study, a total of 63 sows, parity 2 to 7 were divided over 2 treatment groups which were fed either restricted (RESTRICT) or ad libitum (ADLIB) during the peripartum period (day 106 of gestation until day 7 of lactation). Within each treatment group, sows were assigned to 1 of 3 body condition groups based on back fat thickness at day 106 of gestation: <18 mm (LEAN), between 18 and 22 mm (MODERATE), and >22 mm (FAT). Postprandial blood samples were taken on days 107, 109, and 112 of gestation and on days 1, 3, and 5 of lactation. With RIA, leptin, ghrelin, and resistin of each sample were analyzed. For both leptin and resistin, the hormonal profile gradually increased throughout the peripartum period (P < 0.001), whereas ghrelin peaked on day 109 of gestation compared with day 107 of gestation and day 1 of lactation. Other time points were intermediate between those two (P < 0.001). The peripartum profile of leptin was significantly higher for FAT sows than for the 2 other condition groups. No effect of body condition on ghrelin and resistin concentrations was observed. None of the 3 measured hormones were affected by feeding strategy. In conclusion, during the peripartum period feed intake of sows did not affect leptin, ghrelin, or resistin profiles. Leptin was the only hormone investigated that reflected body condition. Although body condition and late gestation feed intake have been previously described as risk factors for peripartum hypophagia, they did not induce hypophagia in any of the sows or affect the profile of the observed feed intake-regulating hormones during the peripartum period.