Gene Expression Profiling of Preovulatory Follicle in the Buffalo Cow: Effects of Increased IGF-I Concentration on Periovulatory Events

The preovulatory follicle in response to gonadotropin surge undergoes dramatic biochemical, and morphological changes orchestrated by expression changes in hundreds of genes. Employing well characterized bovine preovulatory follicle model, granulosa cells (GCs) and follicle wall were collected from the preovulatory follicle before, 1, 10 and 22 h post peak LH surge. Microarray analysis performed on GCs revealed that 450 and 111 genes were differentially expressed at 1 and 22 h post peak LH surge, respectively. For validation, qPCR and immunocytochemistry analyses were carried out for some of the differentially expressed genes. Expression analysis of many of these genes showed distinct expression patterns in GCs and the follicle wall. To study molecular functions and genetic networks, microarray data was analyzed using Ingenuity Pathway Analysis which revealed majority of the differentially expressed genes to cluster within processes like steroidogenesis, cell survival and cell differentiation. In the ovarian follicle, IGF-I is established to be an important regulator of the above mentioned molecular functions. Thus, further experiments were conducted to verify the effects of increased intrafollicular IGF-I levels on the expression of genes associated with the above mentioned processes. For this purpose, buffalo cows were administered with exogenous bGH to transiently increase circulating and intrafollicular concentrations of IGF-I. The results indicated that increased intrafollicular concentrations of IGF-I caused changes in expression of genes associated with steroidogenesis (StAR, SRF) and apoptosis (BCL-2, FKHR, PAWR). These results taken together suggest that onset of gonadotropin surge triggers activation of various biological pathways and that the effects of growth factors and peptides on gonadotropin actions could be examined during preovulatory follicle development

DIGESTIBILIDAD IN VITRO DE DIETAS PARA BECERROS EN CRECIMIENTO ADICIONADAS CON INÓCULO DE LEVADURAS Y BAGAZO DE MANZANA FERMENTADO

Se empleo la técnica de digestibilidad in vitro para evaluar el efecto de la adición de un inóculo de levadura y de bagazo de manzana fermentado en dietas de becerros en crecimiento. Los tratamientos consistieron en: T0 (testigo): heno de avena (HA), ensilaje de maíz (SM) y concentrado; T1 (BMZN): HA, SM y concentrado con 12 % de bagazo de manzana fermentado (BMZN); T2 (IL): HA, SM y concentrado con 2 % de inóculo de levaduras (IL). Se realizó un análisis de varianza en un diseño completamente al azar, tomando muestras por triplicado de cada tratamiento, para medir digestibilidad in vitro de materia seca (MS), de fibra detergente neutro (FDN), de fibra detergente ácido (FDA) y contenido de lignina detergente ácido (LDA) durante 48 h. Así mismo, para evaluar la producción de gas (PG) in vitro, se midieron ácido acético, ácido propiónico, ácido butírico, además, nitrógeno amoniacal (N-NH3), ácido láctico y pH a las 3, 6, 12, 24, 48, 72 y 96 h. El T1 y T2 mostraron diferencia significativa (p<0.05) en la digestibilidad de MS, FDN, FDA y LDA. El T2 fue superior (p<0.05) al T1 y T0 en la PG a las 24, 48, 72 y 96 h. La mayor producción (p<0.05) de AGV lo presentaron el T1 y T2. Estos últimos, mostraron un incremento (p<0.05) en la concentración de N-NH3 y una disminución (p<0.05) de Ác. Láctico, siendo el T2 superior (p<0.05) en el pH. La adición de un IL y de BMZN en la alimentación de becerros en crecimiento es una alternativa ya que mejoran las características nutricionales y fermentativas de la dieta