Sincronização de estro com CIDR reutilizado em cabras lactantes da raça Toggenburg tratadas com somatotropina bovina recombinante (r-bST)[ RESUMOAvaliou-se a resposta de cabras tratadas com r-bST no protocolo de sincronização de estro. Foram utilizadas 26 cabras Toggenburg, divididas em dois tratamentos: T1 (n=13), tratadas com quatro injeções de 250mg de rbST, a intervalos de 14 dias, e T2 (n=13), tratadas com solução salina (controle). Na semana seguinte à última injeção da r-bST, colocou-se o dispositivo intravaginal com progesterona (dia 0), previamente utilizado por cinco dias, e injetou-se PGF 2 (22,5µg) nos animais dos dois tratamentos, e o dispositivo foi retirado no dia 6. Todas as fêmeas em estro foram submetidas à monta natural. A porcentagem de animais em estro e a taxa de gestação foram 76,9 e 70,0 e 84,6 e 72,7%, no T1 e T2, respectivamente. Não houve diferença (P>0,05) na duração do estro, no intervalo tratamento-início do estro, no número de ovulações, nos intervalos: início e final do estro à ovulação e retirada do dispositivo à ovulação entre os animais dos dois tratamentos. O diâmetro médio dos folículos ovulatórios das fêmeas não diferiu (P>0,05). Durante a permanência do dispositivo, as concentrações séricas de progesterona apresentaram valores semelhantes (P>0,05) entre as cabras de T1 e T2. A r-bST não afetou a sincronização de estro.Palavras-chave: caprino, dispositivo intravaginal, estro, taxa de gestação 2 (22.5µg) ABSTRACT The response of goats treated with r-bST in the estrous synchronization protocol was evaluated. Twenty-six Toggenburg females were divided in two treatments: T1 (n=13) treated with four injections of 250mg r-bST, at 14 days intervals, and T2 (n=13) treated with saline solution (control). The intravaginal device previously used by five days was inserted (day 0) one week after the last injection of r-bST and PGF
Indução da ovulação em cabras, fora da estação reprodutiva, com LH e GnRH e com estro induzido por progestágenos [Induction of the out-of-season ovulation (with LH and GnRH)
Altering the lipid composition of sperm plasma membranes affects sperm cryosurvival. Cryopreservation induces many stresses on the spermatozoa, including destabilization of the plasma membrane, which results in the loss of sperm motility and function. Treating bull spermatozoa with cholesterolloaded cyclodextrin (CLC) prior to cryopreservation increases sperm cryosurvival rates. This study compared the effect of adding other sterols, which should incorporate into the membrane and increase membrane fluidity at low temperatures, thereby increasing cryosurvival. Ejaculates from four bulls were divided into two experiments (E). In E1, ejaculates were extended with Tris, and then subdivided into four treatments: No additive (control), 1.5 mg CLC/120 million sperm (positive control), and 1.5 mg/120 million sperm in cyclodextrin pre-loaded with either cholestanol or desmosterol. Spermatozoa were incubated for 15 min at 22�C after which both the ability of fresh spermatozoa to bind to the zona pellucida (ZP) and chicken egg perivitelline membrane (EPM) and their osmotic tolerance were evaluated. In E2, sperm were diluted to 120 million cells mL–1 in a Tris diluent and treated as described for E1. Then, samples were diluted 1:1 (v:v) in Tris with 20% Egg Yolk (EY) and cooled to 5�C. After dilution 1:1 (v:v) with Tris containing 10% EY and 16% glycerol, samples were allowed to equilibrate for 15 min, and then were packaged into 0.5-mL straws, frozen in static liquid nitrogen vapor for 20 min, and plunged into liquid nitrogen for storage. Straws were thawed and the motility and zona-binding ability were determined using a Hamilton Thorne Motility Analyzer (Hamilton Thorne Biosciences, Beverly, MA, USA) and epifluorescence microscopy, respectively. Treatment differences for sperm motility, osmotic tolerance, and zona binding were determined using analysis of variance. Treating spermatozoa with CLC resulted in more fresh bull spermatozoa binding to the EPM and ZP compared to cholestanolor desmosterol-loaded cyclodextrin-treated spermatozoa or control cells (P < 0.05). No differences were observed between EPM and ZP binding (P > 0.05). The percentages of total and progressively motile spermatozoa were higher for fresh samples treated with cholesterol-, cholestanol-, or desmosterol-loaded cyclodextrin than for control cells (P < 0.05) when spermatozoa were exposed to anismotic conditions, and then returned to isosmolality. After cryopreservation, the percentages of motile spermatozoa and number of spermatozoa binding to ZP were similar for spermatozoa treated with CLC (56% and 115 sperm/ZP) and cholestanol (53% and 108 sperm/ZP) compared to spermatozoa treated with desmosterol (42% and 86 sperm/ZP; P < 0.05). All treatments provided higher motility and binding efficiency than control spermatozoa (32% and 62 sperm/ZP; P < 0.05). Therefore, adding cholesterol or cholestanol to bull sperm membranes improved cell cryosurvival. Studies to determine if cholestanol affects sperm capacitation need to be conducted.
Protein and urea concentrations impair oocyte and embryo development in vivo and in vitro through an unclear mechanism. A possible way to understand this process is to determine the concentration of hormones and metabolites in follicular fluid associated with normal development. The objective of this study was to determine the effect of dietary urea levels on follicular fluid concentration of hormones and metabolites and oocyte quality. A trial was conducted with 9 nonpregnant and nonlactating Saanen goats, which had been distributed in a randomized design and fed with diets with 0 (n = 4) and 2.4% of urea in the total dry matter (DM) of the diet (n = 5). Before follicle aspiration by laparotomy, the goats were synchronized by inserting intravaginal sponges containing 60 mg of acetate medroxyprogesterone (Progespon®, Sintex) for 10 days followed by 125 μg of cloprostenol (Ciosin® Coopers) 48 h before the removal of the sponge. The sponge was removed immediately before the follicular aspiration. The follicular development was stimulated with 70 mg of NIH-FSH-P1 (Folltropin V® Vetrepharm) i.m., and 300 IU of eCG i.m., (Novormon® Sintex) given 36 h before the follicular aspiration. Fluid from the 2 lartest follicles of each ovary were analyzed to determine the concentration of estradiol, progesterone, and testosterone by quimioluminesence, and glucose and urea concentrations were measured by enzymatic kit. The other follicles in each ovary were aspired with new needles and syringes and the oocyte quality was recorded. Oocytes were classified according to cytoplasma aspect and number of granulosa cells: Class A (dark cytoplasm and uniform aspect) with 3 (AMG) and <3 layers of cumulus cells (AmG); class B (cytoplasm with color alterations, desuniform aspect and vacuoles) with 3 (BMG) and <3 layers of cumulus cells (BmG); number of partially denuded oocytes (PD) and number of denuded oocytes (DO). Data were analyzed by ANOVA and treatment difference separated by SNK test. Follicular fluid estradiol concentration was lower in goats fed with urea (4.02 ± 0.16; 4.97 ± 0.18 ng mL–1; P < 0.05), progesterone concentration did not differ between treatments (2.48 ± 0.58; 3.37 ± 0.52 ng mL–1; P > 0.05), testosterone concentration was lower in the control animals (1.17 ± 0.48; 3.20 ± 0.43 ng mL–1; P < 0.05). The glucose (91.44 ± 3.60; 84.78 ± 5.58 mg dL–1) and urea concentration (23.04 ± 1.06; 18.00 ± 2.35) were greater in the animals treated with 2.4% compared with 0% of urea (P < 0.05), respectively. The number of oocytes in the different categories was not affected by treatment (P > 0.05): AMG 1.20 ± 1.09 v. 0.50 ± 0.57, AmG 4.20 ± 2.16 v. 3.50 ± 3.10, BMG 0.40 ± 0.54 v. 0.25 ± 0.50, BmG 1.40 ± 0.54 v. 1.75 ± 1.25, DO 10.20 ± 3.76 v. 11.50 ± 5.44, in the 0 and 2.4% of urea groups respectively. Only the number of PD (1.60 ± 0.54 v. 3.50 ± 1.91) recovered from animals treated with 2.4% was greater than in controls (P < 0.05). The hormone and metabolites concentration in follicular fluid as well as the oocyte quality was affected by the urea concentration of the diet. Supported by grant from: CNPq, FAPEMIG, Shering Plough®, Tecnopec®, Carbogel®.
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