Resumen:
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[EN] The present work evaluates how a rabbit line selected for robustness and two other lines
selected for productive criteria, could have affected the physiological maturity and blood
leukocytes counts of young rabbits ...[+]
[EN] The present work evaluates how a rabbit line selected for robustness and two other lines
selected for productive criteria, could have affected the physiological maturity and blood
leukocytes counts of young rabbits at weaning, as well as their possible effect on the subsequent
performance and health status during the growing period. The study was conducted
on a total of 2904 young rabbits weaned at 30 days, belonging to three different genetic
types (line H, founded for litter size at birth and selected for litter size at weaning during 17
generations; line LP, characterised by robustness founded for reproductive longevity criteria
and selected for litter size at weaning for 7 generations; and line R, founded and selected
during 25 generations for average daily gain from the 4th to the 9th week of life). Two different
diets were used during lactation. The two diets were both isoenergetic and isoprotein
buttheir main energy source differed, being either animal fat(AF) or cereal starch (CS). Leucocyte
subsets were characterised at weaning, and growing performance was studied until
58 days of age (feed intake, live weight, mortality by digestive disorders and morbidity) for
both medicated and non-medicated dietary versions. At weaning, young rabbits fed an AF
lactating diet evidenced greater B lymphocyte count(on av. +8.6 ± 3.5 × 106/L; P < 0.05)than
those fed a CS diet. With respectto H and R rabbits, blood from LP ones had higher counts for
total (on av. 591 ± 167 × 106/L; P < 0.05), B (on av. +11.05 ± 4.3 × 106/L; P < 0.05), T CD5+ (on
av. +266 ± 83 × 106/L; P < 0.05) and CD8+ lymphocytes (on av. +72.5 ± 28 × 106/L; P < 0.05),
and with respect to R, higher counts of CD4+ (on av. +121 ± 47 × 106/L; P < 0.05) lymphocytes
(on av. +12.3 ± 4.1 × 106/L; P < 0.05), monocytes (on av. +66 ± 32 × 106/L; P < 0.05) and
granulocytes (on av. +567 ± 182 × 106/L; P < 0.05) at weaning. LP line rabbits also showed
lower mortality by digestive disorders (on av. −8 points of percentage) and morbidity
(on av. −4 points) than those from H and R lines during the growing period (P < 0.05).
R animals presented higher feed intake and daily weight gain, and a lower feed conversion
ratio than H and LP animals (on av. +16.7 ± 2.7 g dry matter/day, +10.3 ± 0.4 g/day and
−0.22 ± 0.04 g dry matter/g, respectively). In conclusion, the foundation of a line for reproductive
longevity, which has been previously reported to give greater robustness (low
environmental sensitivity) to their reproductive stock, could have conferred higher leukocytes
counts at weaning to their offspring, as well as a better ability to confront digestive
disorders as compared to other lines founded or selected exclusively for productive criteria.
© 2014 Elsevier B.V. All rights reserved.
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Agradecimientos:
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This study has been supported by the Interministerial Commission for Science and Technology (CICYT) from the Spanish Government and the General Direction of Universities from the Valencia Government. Grants number ...[+]
This study has been supported by the Interministerial Commission for Science and Technology (CICYT) from the Spanish Government and the General Direction of Universities from the Valencia Government. Grants number AGL2011-30170-C02-01, AGL2011-30170-C02-02 and ACOMP/2013/017 are gratefully acknowledged. Grants for Ana Garcia-Quiros from Universidad CEU-Cardenal Herrera, and Mariola Penades and Alberto Arnau from the Ministerio de Educacion, Cultura y Deporte (AP2010-3907 and BES-2012-052345, respectively) are also gratefully acknowledged.
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