Single Fixed-Time Post-Cervical Insemination in Gilts with Buserelin

Current protocols for gilts recommend the deposit of multiple semen doses in the cervix each 12–24 h after estrus detection. Our objectives were: (1) to determine the effect of buserelin and a single fixed-time artificial insemination using the new post-cervical artificial insemination technique (FTAI-PCAI) on reproductive and productive performance in gilts, and (2) to compare this protocol with conventional estrus detection and double PCAI without hormonal induction. In the control group (C; n = 240), gilts were inseminated twice (8 and 12 h from estrus onset). Gilts in the treatment group (T; n = 226) received buserelin (10 μg, intramuscular) 120 h after altrenogest treatment (18 d) and one single PCAI 30–33 h after buserelin administration. The groups did not differ in reproductive and production performance (p > 0.05). The T group showed greater piglet birth weight and shorter estrus duration (p < 0.001). Delivery batch length differed significantly depending on the season (p < 0.05); the shortest length corresponded to autumn. Both groups only differed significantly in spring (p = 0.018), with a shorter length in the T group. This new FTAI-PCAI protocol with buserelin is recommended in gilts, helping with optimization of genetic diffusion, boars, and semen doses.

Influence of Environmental Temperature and Hormonal Stimulation on the In Vitro Sperm Maturation in Sterlet Acipenser ruthenus in Advance of the Spawning Season

Sturgeon sperm maturation occurs outside the testes during the transit of testicular spermatozoa (TS) through the kidneys and the Wolffian ducts. A method of in vitro TS maturation in sterlet Acipenser ruthenus was used to investigate the effects of temperature and hormonal stimulation of spermiation on the ability of TS to complete this process. Spermatozoa motility parameters after in vitro maturation of testicular sperm, concentrations of sex steroid hormones and testis morphology were studied in three groups of sterlet: (1) after overwintering in ponds (OW), (2) adapted to spawning temperature (ST), and (3) adapted to spawning temperature with hormonal induction of spermiation (ST-HI). Blood plasma concentrations of testosterone, 11-ketotestosterone and 17,20β-dihydroxy-pregnenolone increased significantly after hormonal induction of spermiation (group ST-HI). In all groups, TS were not motile. After in vitro sperm maturation, motility was up to 60% only in group ST-HI. The data suggest that the ability of TS to be matured in vitro was not related to the environmental temperature, while hormonal stimulation of spermiation during the spawning season was an absolute requirement for optimal in vitro maturation.

ADVANCES IN REPRODUCTION OF THE LEBRANCHE MULLET Mugil liza: MATURATION AND SPAWNING OF F1 BREEDERS IN CAPTIVITY

This study aimed to evaluate the reproductive response of mullets born in captivity (F1) using hormonal induction. Therefore, it was described maturation and induced spawning of mullet (Mugil liza) breeders born in captivity (F1). F1 males presented viable sperm at 11 months of age, with length of 25.7 ± 0.4 cm and weight of 205.7 ± 11.5 g. In contrast, at three years of age F1 females could be reproduced, with length of 47.4 ± 1.4 cm and weight of 1263.0 ± 64.6 g. Ten spawnings were conducted, and the average diameter of the oocytes at the time of hormonal induction, fertilization rate, total and relative fertility and hatching rate were recorded. Spawning was attained through hormonal induction in females with oocyte diameter greater than 600 µm and in males that released semen with abdominal massage. During this reproductive period, induced females produced a second group of mature oocytes so another hormonal induction was performed. The present study describes the induction of mullet breeders born in captivity and the possibility of females to be induced more than once during the same reproductive period.

Monitoring the time-grade required for extrusion of oocytes reproductive from colossoma macropomum

The water temperature of the tanks of the breeding herds exerts a strong influence on the process of artificial reproduction. Its monitoring through the hour-degree, serves to assist in the moment to be made the extrusion of the oocytes. The objective was to monitor the time-degree that Colossoma macropomum females need after the second dose of the hormonal induction protocol, until the time of extrusion of their oocytes. The analysis was carried out at the Fish Fishery in the municipality of Sorriso-MT. Nine breeding women were submitted to the protocol of hormonal induction with pituitary extract of carp being administered in two doses. In the former, the dose of 0.5 mg / kg was used and the second dose was 5 mg / kg body weight, with an interval of 12 hours. From the second dose, the temperature in degrees centigrade of the water from the tanks was monitored hourly until the time of oocyte extrusion. Breeders had muscle tremors, swimming in circles, and were more agitated nine hours after the second dose. The oocytes had a yellowish-brown appearance, and some had individual features. The sum of the temperature of the water in hours-degree obtained was of 243. The temperature of the water did not present variation, maintaining itself at 27 ° C. It is concluded that an hour-degree is necessary for an extrusion of oocytes in some of the things you can find in Colossoma Macropomum of 243, agreeing with the limits proposed in the literature.