Effect of photoperiod on sexual activity of boar

The main objective of this study was to assess the effect of photoperiod on sexual activity of three breeds of boars: Swedish Landrace (n=34), Large White (n=38), and Duroc (n=32). Boar sexual activity was analysed based on the libido index and intensity of ejaculation. The libido index was calculated as the ratio between the duration of ejaculation and time of preparation until ejaculation. The intensity of ejaculation was the volume of ejaculate (mL) secreted in the unit of time (min). The effect of photoperiod was analysed as the effect of duration of daylight ( lt 12 h and >12 h) within photoperiod intervals (increasing and decreasing). Impact assessment was carried out by applying the General Linear Model procedure. Libido and intensity of ejaculation varied under the impact of photoperiod and the breed of boars. With the increase in age, the boar libido weakened, while the volume of ejaculate and intensity of ejaculation increased. Boars manifested better libido when the daylight lasted longer than 12 h in both photoperiod intervals. Different from libido, the volume of ejaculate and intensity of ejaculation were highest when the daylight was shorter than 12 h, but only in the decreasing photoperiod interval. Swedish Landrace boars manifested best libido, while in the production of sperm the Duroc boars were inferior compared with Swedish Landrace and Large White. The phenotypic relationship among libido, ejaculate volume, and ejaculation intensity ranges from very low to high; however, the coefficients were positive, which indicates the possibility of simultaneous improvement of these traits

ALTERAÇÕES ENDÓCRINAS EM REPRODUTORES SUÍNOS DE ALTO DESEMPENHO

Objetivando descrever o comportamento sexual e reprodutivo de machos suínos de alto desempenho, submeteram-se os animais a um protocolo de treinamento para colheita de sêmen, a fim de que fossem incorporados ao plantel de reprodutores do Setor de Suinocultura do Departamento de Zootecnia da UFLA. Submeteram-se os animais a medições de biometria testicular e pesagem para avaliações de desenvolvimento dos testículos e ganho de peso diário (GPD) durante a fase pré-púbere. Após o período de treinamento de colheita de sêmen, foram coletadas amostras de sangue para realização de análises hormonais de testosterona, estradiol, FSH e LH plasmáticos. Observaram-se diferenças nas concentrações de testosterona e estradiol, número médio de saltos diários sobre o manequim e tempo médio de ejaculação. O animal A apresentou um volume de 369,68 mL e 412,67 mL, para o testículo direito e esquerdo, respectivamente, em média oito saltos diários sobre o manequim durante o período de treinamento, e o tempo médio de ejaculação foi de 261 segundos. O animal B não realizou nenhum salto durante o treinamento e apresentou volume testicular direito de 359,76 mL e esquerdo de 315,10 mL. As dosagens hormonais para o animal A foram de 0,0153 ng/mL e 0,7015 ng/mL para testosterona e estradiol, respectivamente. O animal B apresentou concentração plasmática de testosterona de 0,0011 ng/mL e 0,0241 ng/mL de estradiol. As concentrações de FSH e LH foram semelhantes entre os animais, sendo 0,10 mU/mL e 0,10 U/L, respectivamente. Essas diferenças observadas possivelmente determinaram o comportamento sexual diferenciado dos machos durante o período de treinamento e colheita de sêmen. PALAVRAS-CHAVES: Comportamento sexual, hormônios, libido, varrão

Matrix Development in Self-Assembly of Articular Cartilage

Articular cartilage is a highly functional tissue which covers the ends of long bones and serves to ensure proper joint movement. A tissue engineering approach that recapitulates the developmental characteristics of articular cartilage can be used to examine the maturation and degeneration of cartilage and produce fully functional neotissue replacements for diseased tissue.This study examined the development of articular cartilage neotissue within a self-assembling process in two phases. In the first phase, articular cartilage constructs were examined at 1, 4, 7, 10, 14, 28, 42, and 56 days immunohistochemically, histologically, and through biochemical analysis for total collagen and glycosaminoglycan (GAG) content. Based on statistical changes in GAG and collagen levels, four time points from the first phase (7, 14, 28, and 56 days) were chosen to carry into the second phase, where the constructs were studied in terms of their mechanical characteristics, relative amounts of collagen types II and VI, and specific GAG types (chondroitin 4-sulfate, chondroitin 6-sulfate, dermatan sulfate, and hyaluronan). Collagen type VI was present in initial abundance and then localized to a pericellular distribution at 4 wks. N-cadherin activity also spiked at early stages of neotissue development, suggesting that self-assembly is mediated through a minimization of free energy. The percentage of collagen type II to total collagen significantly increased over time, while the proportion of collagen type VI to total collagen decreased between 1 and 2 wks. The chondroitin 6- to 4- sulfate ratio decreased steadily during construct maturation. In addition, the compressive properties reached a plateau and tensile characteristics peaked at 4 wks.The indices of cartilage formation examined in this study suggest that tissue maturation in self-assembled articular cartilage mirrors known developmental processes for native tissue. In terms of tissue engineering, it is suggested that exogenous stimulation may be necessary after 4 wks to further augment the functionality of developing constructs