Comparação entre o TRIS, Lactose/TRIS, Ringer-Lactato e Leite Desnatado como diluidores na criopreservação do sêmen bubalino

Abstract

The objective of this experiment was to test the effectiveness of different extenders, the basis of Ringer Lactate, Skim Milk, TRIS (hydroxymethyl-amino-methil Methan) and Lactose/TRIS, the cryopreservation of buffalo semen. We used three male Murrah buffaloes in full sexual activity. The semen was collected by artificial vagina total of 71 ejaculates. After harvest, each sample was subjected to qualitative and quantitative analyzes of semen. The ejaculates were split and diluted in four extenders. The diluted semen was stored in straws of 0,25 mL and subjected to an equilibration time of up to four hours at 5°C, with subsequent freezing in liquid nitrogen. The identified samples were thawed in a water bath at a temperature of 40°C for 30 seconds and subsequently evaluated for motility, vigor, acrosome damage, and percentage of sperm pathologies. The samples were also tested with heat-resistance, while remaining incubated at 40°C for 30 seconds, 3-5 minutes, 30 minutes, 1 hour, 2 hours and 3 hours, which were evaluated for motility and spermatic . The physico-chemical, after fresh semen analysis, were within the prescribed values for buffaloes and satisfactory for the freezing process. After thawing the semen, observed numerical reduction (p<0,05) in sperm motility, with fresh semen was found 86,67±6,17% decreasing to 70±6,92% in TRIS, 67,4±8,01% in Ringer/lactate, 67,09±9,03% in Lactose/TRIS and 59,7±9,05% in skim milk and to compare between the four treatments only the skimmed milk showed a statistically significant difference (p<0,05). After thawing, spermatic vigor also decreased significantly (p<0,05) in four treatments (3,50±0,53 TRIS, 3,38±0,49 Ringer's lactate, 3,3±0,46 Lactose/TRIS and 3,25±0,44 Skim milk) versus (4±0,39 fresh semen) and when comparing between treatment, only between skimmed milk and TRIS was no statistical difference (p<0,05). As for the larger defects (4,15±1,9% fresh semen; 10,51±4,4% TRIS, 11,94±4,2% Ringer's lactate, 11,88±4,8% Lactose/TRIS; 12,01±5% skim milk), smaller (3,81±1,2% fresh semen and 4,67±1,1% TRIS, 4,98±1,7% Ringer's lactate, 4,93±2,0% Lactose/TRIS, 4,93±2,0% skimmed milk) and total (7,91±2,1% fresh semen; 15,18±4,7% TRIS, 16,92±4,8% Ringer's lactate, 16,82±5,6% Lactose/TRIS, 17,11±5,6% skimmed milk), after thawing showed a significant increase of defects in the four treatments (p<0,05), and among them were not statistically different between groups (p>0,05). In the post-TTR after 3 hours of incubation, progressive motility (21,13±7,5% TRIS; Ringer lactate 20,78±7,4%; Lactose/TRIS 20,25±5,3%; Skimmed milk 20,12±6,6%) and spermatic vigor (TRIS 2,04±0,5, Ringer Lactate 2,07±0,5, Lactose/TRIS 2,02±0,4, 2 skim milk, 2,00±0,5) showed no statistical difference between treatments (p<0,05). As for intergridade acrosome after thawing (semen in natura 97,85,±0,6%; TRIS 91,65±4,3%, Ringer-Lactate 90,46±4,8%; Lactose/TRIS 89,76±5,4%; Skimmed milk 90,56±5,6%), decreased (p<0,05) and when comparing this parameter between treatments was not observed statistically significant differences between the treatment (p>0,05). Given the observed results we conclude that the freezing of buffalo semen extenders with TRIS (Tris-hydroxy-methyl-amino-Methan), Ringer Lactate, Lactose / TRIS and skimmed milk showed satisfactory function in cryoprotection of sperm viability semen in different stages of cryopreservation.