Growth and development of adipose tissue and gut and related endocrine status during early growth in the pig: impact of low birth weight

146

136

The aim of this review article is to provide an overview of the role of pigs as a biomedical model for humans. The usefulness and limitations of porcine models have been discussed in terms of metabolic, cardiovascular, digestive and bone diseases in humans. Domestic pigs and minipigs are the main categories of pigs used as biomedical models. One drawback of minipigs is that they are in short supply and expensive compared with domestic pigs, which in contrast cost more to house, feed and medicate. Different porcine breeds show different responses to the induction of specific diseases. For example, ossabaw minipigs provide a better model than Yucatan for the metabolic syndrome as they exhibit obesity, insulin resistance and hypertension, all of which are absent in the Yucatan. Similar metabolic/physiological differences exist between domestic breeds (e.g. Meishan v. Pietrain). The modern commercial (e.g. Large White) domestic pig has been the preferred model for developmental programming due to the 2-to 3-fold variation in body weight among littermates providing a natural form of foetal growth retardation not observed in ancient (e.g. Meishan) domestic breeds. Pigs have been increasingly used to study chronic ischaemia, therapeutic angiogenesis, hypertrophic cardiomyopathy and abdominal aortic aneurysm as their coronary anatomy and physiology are similar to humans. Type 1 and II diabetes can be induced in swine using dietary regimes and/or administration of streptozotocin. Pigs are a good and extensively used model for specific nutritional studies as their protein and lipid metabolism is comparable with humans, although pigs are not as sensitive to protein restriction as rodents. Neonatal and weanling pigs have been used to examine the pathophysiology and prevention/treatment of microbial-associated diseases and immune system disorders. A porcine model mimicking various degrees of prematurity in infants receiving total parenteral nutrition has been established to investigate gut development, amino acid metabolism and non-alcoholic fatty liver disease. Endoscopic therapeutic methods for upper gastrointestinal tract bleeding are being developed. Bone remodelling cycle in pigs is histologically more similar to humans than that of rats or mice, and is used to examine the relationship between menopause and osteoporosis. Work has also been conducted on dental implants in pigs to consider loading; however with caution as porcine bone remodels slightly faster than human bone. We conclude that pigs are a valuable translational model to bridge the gap between classical rodent models and humans in developing new therapies to aid human health.

Section: Litten-brown Corson and Clarkementioning

confidence: 99%

Porcine models for the metabolic syndrome, digestive and bone disorders: a general overview

Litten-Brown

Corson

Clarke

2010

146

136

“…In pigs, decades of intensive genetic selection has brought larger litters but more very low birth weight pigs (,1 kg) and higher within-litter birth weight variation (Morise et al, 2008). Very low birth weight pigs (runts) account for 10% to 15% of littermates with mortality statistics typically between 9% and 12% of all neonates (Ramsay et al, 2010), but as high as 50%.…”

Section: Other Considerationsmentioning

confidence: 99%

Leptin in farm animals: where are we and where can we go?

Wylie

2011

Fat affects meat quality, value and production efficiency as well as providing energy reserves for pregnancy and lactation in farm livestock. Leptin, the adipocyte product of the obese (ob) gene, was quickly seen as a predictor of body fat content in animals approaching slaughter and an aid to assessing reproductive readiness in females. Its participation in inflammation and immune responses that help animals survive infection and trauma has clear additional relevance to meat and milk production. Furthermore, almost a decade of discoveries of nucleotide polymorphisms in the leptin and leptin receptor genes has suggested useful applications relating to feed intake regulation, the efficiency of feed use, the composition of growth, the timing of puberty, mammogenesis and mammary gland function and fertility in cattle, pigs and poultry. The current review attempts to summarise where research has taken us in each of these aspects and speculates on where future research might lead.Keywords: leptin, farm animals, production efficiency, fat, body composition ImplicationsLeptin has not yet delivered the initial expectations of animal scientists eager for a robust and reliable marker of body and carcase fat in farm livestock, but its close association with fat and fat deposition continue to cast it as a potential aid for enhancing production efficiency, reproductive success and immune function. Polymorphisms in the leptin and leptin receptor genes provide powerful additional tools for enhanced selection to meet aspirations for increased global animal production within an overarching need to contain and reduce environmental impacts. IntroductionFat is important in all livestock production as it affects product quality and production efficiency and provides the energy reserves for pregnancy and lactation. The discovery of the obese (ob) gene and its product leptin (Zhang et al., 1994;Halaas et al., 1995) and their links to body fat (Frederich et al., 1995;Maffei et al., 1995) excited animal scientists, who quickly saw potential for leptin as a predictor of body composition in animals approaching slaughter and of reproductive readiness in females (Hossner, 1998). Its involvement in inflammation and in the immune responses that help animals survive infection and trauma, also has clear relevance and attention turned to using leptin, directly or indirectly, to influence production characteristics with feed intake, body composition, puberty, mammary gland function, immune response and the reproductive pathway all possible targets. Associations of production traits with polymorphisms in the leptin and leptin receptor genes pointed to additional applications.Among the many reviews of leptin, those by ), Baile et al. (2000, Ingvartsen and Boisclair (2001), Chilliard et al. (2005) and Barb et al. (2006) stand out as most relevant to livestock with Williams et al. (2002), Barb and Kraeling (2004), Barb et al. (2005) and Zieba et al. (2005) emphasising its involvement in reproduction. Those by Ahima and Flier (2000) and Harris (200...

“…In addition, this has been exacerbated during the last decades where intensive selection for increased litter size in pig production has led to larger litter variation in birth body weight (BW) with the consequences that more piglets are stillborn and born small with a low survival rate (Milligan et al, 2002). Furthermore, low birth body weight (LBW) pigs, as a result of IUGR, may have some (Nissen et al, 2004;Gondret et al, 2006;Morise et al, 2008;Rehfeldt et al, 2008) negative -E-mail: Niels.Oksbjerg@Agrsci.dk consequences on carcass and meat-quality traits like pH, drip loss, tenderness and meat colour.…”

Section: Introductionmentioning

confidence: 99%

Birth weight and postnatal dietary protein level affect performance, muscle metabolism and meat quality in pigs

Nissen

Oksbjerg

2011

Intrauterine growth restriction (IUGR), resulting in low birth body weight (LBW) occurs naturally in pigs. However, IUGR may also cause persistent changes in physiology and metabolism resulting in poorer performance, organogenesis and meat quality. As IUGR pigs have a lower daily gain from birth to slaughter they may differ in utilization of nutrients and requirements for dietary protein compared with their larger littermates. Thus, the objective in this study was to examine the interaction between birth body weight (BW) and the postnatal dietary protein level, in relation to postnatal performance, organogenesis, muscle metabolism and meat quality. The experiment was carried out with offspring from 16 purebred Danish Landrace gilts mated to Danish Landrace boars. The female and entire male pigs with LBW that survived at weaning were compared with the female and male pigs with the highest/high birth body weight (HBW) within each litter. The offspring were reared individually from weaning and were fed ad libitum a diet containing either a normal level of protein (NP) for optimal growth or an isocaloric diet containing a 30% lower protein content (LP) from 3 weeks to 150 days of age. At slaughter, we found no interactions between birth weight group and dietary protein level for any of the measured traits. The relative crown-rump length (cm/kg) at birth indicates that LBW pigs were thinner than HBW pigs. Daily gain and feed intake were reduced by 14% and 10%, respectively, while the kg feed/kg gain was slightly increased by 3% in LBW pigs compared with HBW pigs. The LP diet reduced daily gain by 27% due to reduced feed intake and increased kg feed/kg gain by 12% and 21%, respectively compared with the NP diet. LBW male pigs produced meat with a higher shear force than male HBW pigs and also LP pigs produced meat with higher shear force than NP pigs. The activity of lactate dehydrogenase in the Longissimus dorsi muscle (LD) was reduced in pigs fed the LP diet. Calpastatin was increased in LD of LBW pigs and decreased in pigs fed the NP diet. In conclusion, these results suggest a rejection of our hypothesis that low birth weight littermates have a lower requirement for dietary protein compared with heavy weight littermates. Furthermore, LBW male pigs and LP fed pigs of both genders produced less tender meat than HBW pigs or NP fed pigs, respectively.