Piglet birthweight and sex affect growth performance and fatty acid composition in fatty pigs

Abstract

This study aimed to determine the effects of piglet birthweight (BIW) and sex, and within-litter BIW variation, on postnatal growth traits and meat quality in fatty breeds of pig. In total, 406 crossbred piglets (half male, half female) born to Iberian sows were studied during their postnatal development until slaughter. After birth, piglets were classified into four BIW categories: very low, low, medium and high. There was a negative effect of low BIW on growth patterns and fatty acid (FA) composition, but effects of litter size and within-litter BIW variation were not found. The very low BIW piglets underwent a period of significant catch-up growth (P < 0.005) relative to high BIW piglets during the early postnatal phase, but also showed a higher feed conversion rate and lower average daily weight gain (P < 0.05 for both measures) throughout the study period. BIW affected development during the entire productive life, and the sex effect increased with age. As a result, the period to reach market weight was longer in very low BIW piglets, by 43 days for females and 15 days for males, compared with their high BIW counterparts. BIW and sex also influenced amount of intramuscular fat, n-3 FA content and monounsaturated FA composition. The study indicates that BIW, modulated by sex, is a critical point for productive traits in fatty pigs. These results provide a basis for future strategies to enhance productive efficiency and meat quality of traditional swine breeds.

Differential Effects of Litter Size and Within-Litter Birthweight on Postnatal Traits of Fatty Pigs

“…The results of the experiment aiming to determine the effects of BIRTH-WEIGHT showed, as expected, similar results to previous studies on both commercial lean strains [9,13] and traditional fatty pigs [19,20,35]. In brief, in agreement with the experimental design, the piglets selected as representative of LBW showed, at birth, significantly lower body weight and size (trunk length and abdominal and thoracic circumferences) than the piglets selected as NBW.…”

“…In brief, LBW piglets were still affected by growth restriction during the post-weaning period (25-75 days old), in spite of developing a higher fractional growth rate than NBW counterparts. They also showed compensatory catch-up growth only during the late-growing period (75-180 days old), as already observed in previous studies in LBW Iberian crossbred pigs [20]. On the other hand, piglets from large litters showed a very early catch-up growth during the post-weaning period (25-75 days old) which slowed down during the late-growing period, when pigs from small litters were initiating their fattening period.…”

“…There were no main differences between LBW and NBW pigs in the BIRTH-WEIGHT trial in the FA profile of brain, liver, and subcutaneous fat-results which are very different from previous studies in Iberian pigs [19,20]. However, we should bear in mind that, in contrast to these previous studies, the pigs currently studied were sampled at an earlier age, prior to the fattening period.…”

“…In the case of the Iberian pig, there is scarce information about the effects of litter size and birthweight on postnatal development. There have been only a couple of studies using crossbred Iberian × Duroc individuals [19,20], which support a influence similar to that of lean breeds of prenatal conditions and birthweight on postnatal development and meat and carcass quality of offspring under farm conditions. Moreover, birthweight is an even more critical subject of study for productive traits in traditional pigs, because the effects increase with offspring age and traditional pigs are characterized by longer cycles than lean pigs.…”

Maternal Transmission Ratio Distortion in Two Iberian Pig Varieties

“…The lack of information about the TRD phenomenon is more considerable in traditional swine breeds, such as the Iberian breed, because of their lower commercial interest and the scarcity of their organized breeding programs compared to modern swine breeds [ 27 , 28 , 29 ]. However, the interest in these traditional breeds is increasing in recent decades due to their high-quality pork products and socio-economic effects, and the Iberian breed is one of the most important worldwide from an economic point of view [ 30 , 31 , 32 ]. Traditional swine breeds also have high genetic diversity [ 33 , 34 , 35 ].…”