Biology of leptin in the pig

To determine possible mechanisms of action that might explain the nutrient partitioning effect of betaine and conjugated linoleic acid (CLA) in Iberian pigs and to address potential adverse effects, twenty gilts were restrictively fed from 20 to 50 kg BW Control, 0.5% betaine, 1% CLA or 0.5% betaine 1 1% CLA diets. Serum hormones and metabolites profile were determined at 30 kg BW and an oral glucose test was performed before slaughter. Pigs were slaughtered at 50 kg BW and livers were obtained for chemical and histological analysis. Decreased serum urea in pigs fed betaine and betaine 1 CLA diets (11%; P 5 0.0001) indicated a more efficient N utilization. The increase in serum triacylglycerol (58% and 28%, respectively; P 5 0.0098) indicated that CLA and betaine 1 CLA could have reduced adipose tissue triacylglycerol synthesis from preformed fatty acids. Serum glucose, lowdensity lipoprotein (LDL) cholesterol and non-esterified fatty acids were unaffected. CLA and betaine 1 CLA altered serum lipids profile, although liver of pigs fed CLA diet presented no histopathological changes and triglyceride content was not different from Control pigs. Compared with controls, serum growth hormone decreased (20% to 23%; P 5 0.0209) for all treatments. Although serum insulin increased in CLA, and especially in betaine 1 CLA pigs (28% and 83%; P 5 0.0001), indices of insulin resistance were unaffected. In conclusion, CLA, and especially betaine 1 CLA, induced changes in biochemical parameters and hormones that may partially explain a nutrient partitioning effect in young pigs. Nevertheless, they exhibited weak, although detrimental, effects on blood lipids. Moreover, although livers were chemically and histologically normal, pigs fed CLA diet challenged with a glucose load had higher serum glucose than controls.

Section: Discussionmentioning

confidence: 85%

Impact of dietary betaine and conjugated linoleic acid on insulin sensitivity, protein and fat metabolism of obese pigs

Fernández‐Fígares

Lachica

Martín

et al. 2012

“…Research on leptin in many different species, including humans, has revealed that this hormone is related to energy metabolism (Barb et al, 2001;Budak et al, 2006). Moreover, levels of leptin in sows can vary in relation to the feeding level (Quesnel et al, 2009), feed composition, time after transition from one feed to another (Papadopoulos et al, 2009) and body condition, mostly measured as back fat thickness (Prunier et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

“…In this study, both feeding scheme and body condition of all sows were similar, resulting in similar fasting leptin levels at the first day of lactation for both treatment groups. Given the inducing role of leptin in insulin resistance, as reviewed by Barb et al (2001), these similar leptin levels likely reduced the chance of finding differences in glucose tolerance induced by different dietary treatments. Fasting NEFA levels were also similar between treatments, indicating a similar amount of energy mobilized from fat reserves in both treatment groups.…”

Section: Discussionmentioning

confidence: 99%

Effect of N,N-dimethylglycine supplementation in parturition feed for sows on metabolism, nutrient digestibility and reproductive performance

Cools

Maes

Buyse

et al. 2010

The current pilot study assessed the influence of N,N-dimethylglycine (DMG) on insulin sensitivity, glucose and fat metabolism, nutrient digestibility and reproductive performance of sows in the peripartal period. At day 105 of gestation, 25 sows were randomly assigned to the control (n 5 13) or the DMG group (n 5 12). Sows from the DMG group were supplemented with 1 g DMG/kg feed until day 3 of lactation. After an overnight fast 1 day after farrowing, a blood sample of each sow was drawn. The plasma was analyzed for insulin, glucose, fructosamine, leptin, thiobarbituric acid reactive substances (TBARS), ferric reducing ability of plasma (FRAP), non-esterified fatty acids (NEFA) and triglycerides (TG) and an oral glucose tolerance test was performed. A rectal feces sample was collected and the apparent fecal digestibility (AFD) of crude fat (CFAT), crude protein (CP) and nitrogenfree extract (NFE) was calculated after proximate analyses. Finally, a colostrum sample was collected from each sow and analyzed for the presence of DMG. Reproductive performance parameters were recorded. The results showed an improvement in the AFD of CFAT, CP and NFE when DMG was supplemented. This beneficial effect confirms the hypothesis that DMG acts as an emulsifying agent. The improvement in digestibility in the DMG group was accompanied by a numerical increase in plasma TG (P 5 0.067). Plasma NEFA concentrations were not different between treatment groups. DMG supplementation neither affected glucose clearance nor influenced plasma insulin, glucose, fructosamine or leptin levels. TBARS and FRAP also remained unaffected, despite previously reported anti-oxidative properties of DMG. Furthermore, no significant impact on reproductive performance could be recorded. In conclusion, DMG supplementation significantly improved nutrient digestibility. Possible beneficial effects on energy metabolism and reproductive performance of sows should be tested when DMG is supplemented for a longer period of time or at a higher dose.Keywords: sow, N,N-dimethylglycine, nutrient digestibility, glucose metabolism, reproduction ImplicationsThe supplementation of N,N-dimethylglycine (DMG) in parturition feed of sows has an emulsifying effect. This resulted in improvements in not only fat digestibility, but also the digestibility of the protein and the nitrogen-free dietary fraction. However, measures of reproductive performance were not affected by DMG supplementation. The addition of this supplement to gestation and lactation feed should be investigated. Supplementation of DMG over a longer period of time can possibly be beneficial in terms of sow body condition and reproductive performance of sows.

“…Leptin is the protein product of the obese (ob) gene and is involved in the regulation of food intake, BW and whole body energy balance in adults (Friedman and Halaas, 1998;Barb et al, 2001). Its role in the neonate is less documented.…”

Section: Leptinmentioning

confidence: 99%

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

Morise

Louveau

Huërou‐Luron

2008

With genetic selection, the increase in litter size has led to higher variation in within-litter birth weights in pigs. This has been associated with a reduction in mean birth weights and a rise in the proportion of piglets weighing less than 1 kg at birth. Low birth weight pigs exhibit lower postnatal growth rates and feed efficiency, which may be explained by an inadequate digestion and/or nutrient use as a consequence of prenatal undernutrition. It is now documented that there is a relationship between birth weight and subsequent pattern of growth and development of tissues and organs. During the neonatal period, the rapid somatic growth is accompanied by tremendous anatomical, physiological and chemical composition changes. The present review focuses primarily on the influence of low birth weight on adipose tissue and the gastrointestinal tract growth and development during the suckling period. The importance of the somatotropic axis, insulin, thyroid hormones, glucocorticoids, epidermal growth factor and leptin in the regulation of these developmental processes is also considered.