Emprego de diferentes doses de LH suíno na indução e sincronização da puberdade em marrãs

GAMA, R. D. Use of different doses of Swine LH in puberty induction and synchronization in gilts. [Emprego de diferentes doses de LH suíno na indução e sincronização da puberdade em marrãs]. 2003. 77 f. Dissertação (Mestrado em Reprodução Animal) Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Pirassununga, 2003. The research carried out at the Swine Research Laboratory, of FMVZ – USP, Campus of Pirassununga, studied the effects of the use of different hormonal doses on the induction and synchronization of puberty in gilts. Sixty-seven Camborough 22 Agroceres PIC females with 140 days of age and 86kg of body weight were submitted to the following treatments: control T1 (n=21) – use of 600 IU of eCG (equine chorionic gonadotrophin) (Novormon) and 72 hours later 5,0 mg of LH (Luteinizing hormone) (Lutropin – V); treatment 2 T2 (n = 23) – 600 UI of eCG (Novormon) and 72 hours later 2,5mg of LH (Lutropin – V) and treatment 3 T3 (n = 23) 600 UI of eCG (Novormon) and 72 hours later 1,25mg of LH (Lutropin – V). Adult boar stimulation was implemented twice a day, and ovulation was detected through transcutaneous ultrasonography and ovulation rate by corpora lutea (CL) counting at slaughter. The percentage of estrus was similar in T1 (42,85%), T2 (60,87%) and T3 (52,18%), and there was no significant statistic difference (P=0,418). The percentage of females with cystic degeneration was 33,33% (T1); 39,13%(T2) and 39,13%(T3), being no significant difference between the treatments (P=0,9057). The best interval between treatment and estrus (LH – OV) occurred in the group of females submitted to T2 (38,26 ± 2,84) demonstrated by lesser dispersion of the deviations comparing to T1 (37,17 ± 4,07) and T3 (36,25± 5,69); standard deviation was statistically different from T3, but similar to T1, and T1 was also similar to T3 (P<0,05). The interval between the administration of eCG and estrus in T1 (85,33 ± 12,64 hours), T2 (84,40 ±17,50 hours) and T3 (89,14 ± 14,66 hours) were similar, and there was no significant statistic difference (P= 0,6954). The duration of estrous was similar among the three treatments (P = 0,2653), being 41,44 ± 16,30 hours (T1); 48,57 ± 16,29 hours (T2); 39,33 ± 11,42 hours (T3). The number Corpus Luteum in T1 was 9,61 ± 5,43 (1-25); in T2 was 9,86 ±3,32 (1-16); in T3 was 8,13 ± 5,52 (0-20), and there was no significant difference (P=0,4259). The minor deviations observed in treatment T2 suggest that the association of 600 UI of eCG followed by 2,5 mg of LH after 72 hours, was more effective in the induction and synchronization of estrous and ovulation in pre-puberty female swine, considering the experimental methodology used. In the second part of the experiment, artificial insemination was performed at determined timing following two different programs (E). E1 received a single dose 36 hours after administration of LH and E2 received the first dose after 24 hours and the second dose 36 hours after the administration of LH. The gilts were slaughtered with 5 days of pregnancy and the embryos were collected. No statistic difference was observed among the values obtained for recovery rate (36,81±5,21 for E1 and 36,91±4,62 for E2), embryonary viability rate (TVE) (59,28±6,91 for E1 and 62,25±6,26 for E2), fecundation rate (TF) (72,60±7,06 for E1 and 79,33±6,26 for E2) and number of total structures (3,41±0,57 for E1 and 3,77±0,50 for E2) among E1 and E2. There was significant interaction between treatment and the number of doses of semen for the values TVE (T1=60,51± 8,18, T2=68,64±7,94 and T3=53,14±7,8) and TF (73,50±8,36 for T1, 89,93±8,11 for T2 and 64,46±8,05 for T3) (P=0,0036). New research involving the use of hormones and the number of doses of semen need to be repeated.