Full text
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| Author(s): |
Octávio Henrique Orlovsky Eckhardt
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Pirassununga. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD) |
| Defense date: | 2009-12-17 |
| Examining board members: |
Anibal de Sant Anna Moretti;
Paulo Henrique Franceschini;
Francisco Palma Rennó
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| Advisor: | Anibal de Sant Anna Moretti |
| Abstract | |
The present study evaluated the relationship between different nutritional managements in the last third of gestation associated or not with exogenous gonadotropins hormonal protocol at weaning and the manifestation of second litter reduction in female swine. The experiment was carried out in the Laboratory of Swine Research (VNP-FMVZ-USP) Pirassununga/SP. Twenty three (23) pregnant gilts were used in a completely random factorial design, with one factor being the nutritional management from 75 ± 1,74 days of gestation onward, feeding animals with 2,9 kg/day of a pre-lactation diet (P; 3.203 kcal ME/kg, 17,25% CP) or 2,5 kg/day of a gestation diet (G; 2.930 kcal ME/kg, 16,43% CP), and the second factor being the hormonal protocol 600IU of eCG and, after 72 hours, 2,5mg of porcine LH administration (H) or not (C) at weaning. Weekly, from day 82 of gestation until weaning, body weight were measured and blood samples were collected for determinations of serum bioquimical parameters. Females were slaughtered 4,55 ± 0,92 days after artificial insemination for embryo collection and evaluation. Animals in the P treatment showed higher body weight gains (p<0,050) un three of the five weeks evaluated in the late gestation, obtaining higher overall weight gain between days 75 of gestation and the pre partum evaluation (p<0,001). In the lactation period, treatment P showed higher weight losses in the 1st(p=0,038) and 3rd(p=0,061) weeks. No differences in feed consumption during lactation, litter performance and post weaning return to reproductive activity were observed. In the embryo evaluation, an interaction between factors was observed for the percentage of fecundated structures (p=0,051), with values of 98,55%, 78,97%, 96,88% e 99,09% for GC, GH, PC e PH, respectively. Such result indicates a effect of the metabolic state on the response to the hormonal therapy, with the need of further studying the mechanisms involved. Animals submitted to the hormonal protocol showed a higher percentage of embryos in the morula stage (p=0,050). Changes in embryo quality associated with the administration of exogenous gonadotropins might be linked to shifts in follicular growth, leading to the ovulation of oocites of lower quality and altered future embryo development. Females fed the pre-lactation diet had higher total cholesterol and fractions (HDL, LDL, VLDL) in the gestation period, which is linked to the higher consumption of energy yielding substances, and higher concentrations of non-sterified fatty acids (NEFA) during farrowing and lactation, which are related to more severe fat mobilization. In the context of the present experiment, the catabolism during lactation, when moderate and accompanied by higher body reserves at farrowing, did not significantly interfere with the post-weaning reproductive performance. The induction of more severe catabolic states might contribute to enhance our knowledge on the effects of this metabolic state on the reproductive outcome of sows. (AU) | |