Efeitos climáticos sobre parâmetros seminais, morfológicos e fisiológicos em búfalos na Amazônia

Abstract

The presente study was undertaken with the objective of evaluating the influence of climatic variables on parameters of ejaculates of Murrah buffalo bulls raised in humid tropical Amazonian climate, with the specific objectives of analyze biochemical parameters of fructose (Fru), albumin (Alb), total plasmatic protein (TPP), calcium (Ca), phosphorus (P) and magnesium (Mg), evaluate some physiological parameters such as heart frequency (HF), respiratory frequency (RF), rectal temperature (RT) and superficial temperature (ST), and to analyze morphometric data of weight (W), scrotal circumference (SC) and thoracic perimeter (TP) during the rainy and non-rainy periods in Amazon region. Five buffaloes (n=5), average of age 2.5 ± 0.5 years and body weight 450.0 ± 35.5 kg were selected from a group of 12 adult bulls, using a pre-evaluation, through clinical and andrological examination, as donors of semen, chosen based on the best quality of the ejaculates, collected by the artificial vagina method. The experiment was carried out in the municipality of Santarém, Meso-region of Lower Amazonas, West of Pará State, in the área of the Agricultural Exposition Park of the Rural Syndicate of Santarém, with experimental animals kept in lairage regime, separated in individual stalls and fed with the grass Echinochloa polystachya (Canarana-de-pico) ad libitum and supplemented with two kg of a comercial feed, composed by corn, soy and sorghum (with 16% crude protein). The animals had constant access to fresh and clean water, as well as mineral salt ad libitum in a trough. The sanitary control was carried out according to pre-established criteria for the species. The experimental period was divided into two phases: rainy season (RS), from February to May, and non rainy season (nRS), from August to November 2016. The ejaculates were collected twice a week (n=30) per bull, namely 10 ejaculates in the RS and 20 ejaculates in the nRS period, totaling (n=150) samples for analysis, The evaluations physical and morphological of the semen samples were performed with fresh semen, immediately after each collection. The immediate analyzes pertinent to the physical and morphological characteristics of the ejaculates were carried out and corresponded in the RS volume of 3.4 ± 2.0 mL; mass activity of 4.4 ± 0.5; motility of 80.4 ± 5.6%; vigour of 4.4 ± 0.4; concentration of 657.300 ± 237.865,1 x106sptz / mL; major defects of 9.0 ± 2.6%; minor defects of 11.2 ± 3.9%; total defects 2of 0.2 ± 5, 3% and sperm plasma membrane integrity (SPMI) 84.8 ± 5.6%, where as in the nRS, the results were 4.0 ± 2.1 mL; mass activity of 3.0 ± 1.0; motility of 56.2 ± 13.4%; vigour of 3.0 ± 1.0; concentration of 586,000 ± 291,925.9 x106sptz / mL; major defects of 20.8 ± 9.9%; minor defects of 27.5 ± 6.3%; total defects 48.3 ± 9.3% and SPMI of 57. 9 ± 12.4%. Furthermore, it was observed a statistical difference (P<0,01) for the parameters mass activity, motility, vigour, major defects, minor defects, total defects and sperm plasma membrane integrity between the both periods. The biochemical parameters of semen, fructose, albumin, calcium and phosphorus presented a statistical significant difference between both periods (P<0,01)), unlike total plasma proteins and albumin (P>0,01). The mean data for Fru were 17.1 ± 5.6 mg/dL and 10.7 ± 5.6 mg/dL for RS and nRS, respectively. Likewise, in relation to the other components studied, the ratio between a TPP 1.6 ± 0.5 g/dL and 1.7 ± 0.6 g/dL, to Alb 0.45 ± 0.1 g/dL and 0.3 ± 0.1 g/dL, Ca 20.6 ± 2.2 mg/dL and 19.6 ± 2.3 mg/dL, P 11.6 ± 4.6 mg/dL and 7.8 ± 4.5 mg/dL, Mg 2.6 ± 0.5 mg/dL and 2.7 ± 0.7 mg/dL, for RS and nRS, respectively. The morphometry data, such as SC, TP and W, did not present any significant difference between both the studied periods (P>0,01). the data for SC were 28.32 ± 2.3 cm and 28.28 ± 1.8 cm; for the TP were 189.09 ± 14.28 cm and 187.06 ± 11.05 cm; and for W, which were 477.46 ± 112.6 kg and 473.45 ± 84.48 kg; not RS and not nRS, respectively. The data on heart frequency, surperficial temperature (head, back, groin and scrotal pouch) showed statistical difference between both periods (P<0,01). However, the relative data, for RF and TR did not show any difference between both periods (P>0,01). The HF data were 54 ± 10.9 bpm and 48 ± 11.8 bpm; RF 22 ± 6.8 mpm and 23 ± 6.7; RT, 38.3 ± 0.8 oC and 38.2 ± 0.8 oC; ST, in the head region (STH) were 33.3 ± 2.5 °C and 36.2 ± 2.4 °C; in the back region (STB) 33.6 ± 2.1 oC and 35.1 ± 2.1 oC; in the groin (STG) 32.3 ± 2.2 oC and 34.6 ± 2.2 oC; and scrotal pouch (STS) 30.3 ± 2.0 oC and 32.3 ± 2.0 oC, RS and nRS, respectively. The biochemical parameters of the semen for fructose, calcium and phosphorus were those that differed statistically in the rainy and non-rainy seasons, presenting better results in the rainy season. The physiological parameters that were influenced by the non-rainy period, compared to the rainy season were heart rate and surface temperature, of head, back, groin and scrotal pouch. The morphometric data of scrotal circumference, thoracic perimeter and weight did not vary during the periods studied.