Milk replacers supplemented with either L-arginine or L-carnitine potentially improve muscle maturation of early reared low birth weight piglets from hyperprolific sows

Abstract

As a result of the selection for genotypes with greater sow prolificacy, litter size increased and, concomitantly, average litter birth weight and early postnatal survival rates of low birth weight (L-BtW) offspring decreased. This study compared the impact of l-carnitine (CAR) and l-arginine (ARG) supplemented with a milk replacer and fed to L-BtW piglets born from large litters from days 7 to 28 of age on growth performance, carcass composition, organ and Semitendinosus muscle (STM) development. A total of 30 female and castrated Swiss Large White piglets weaned at 7 days of age were assigned to three milk replacer diets containing either no supplement (CON), CAR (0.40 g/piglet per day) or ARG (1.08 g/kg BW per day). Piglets were kept in pairs in rescue decks (0.54 m2). They were weighed daily and daily allowance of both, feed and ARG, was adjusted accordingly. Thus, feed allowance depended on growth. Each day, the milk replacer was prepared with water (1:4). Feed (allowance: 60 g dry matter/kg BW per day) was offered daily in six equal rations. Feed intake and feed efficiency was assessed for the pairs and apparent total tract-energy and -protein digestibility was determined from days 21 to 28 of age. On day 28, piglets were euthanized, blood samples were collected and the whole STM and organs were weighed. In STM, the size and metabolic properties of myofibers were determined. No difference in growth performance was found between dietary treatments, but piglets from the CAR group tended (P<0.10) to grow faster during the 1st experimental week and consume more feed from days 14 to 21 as compared with piglets of the CON group. A setback in growth in the last week in the CAR group coincided with the lower (P<0.05) energy and protein digestibility. Dietary treatments had no effect on STM and organ weight and myofiber size. Compared with the other groups, there were trends (P<0.10) for blood serum urea and glucose level to be greater in CAR and for non-esterified fatty acid level to be greater in ARG piglets. The greater (P<0.05) ratio of lactate dehydrogenase to either citrate synthase or β-hydroxyacyl-CoA dehydrogenase indicated that the relative importance of the glycolytic compared with the oxidative pathway was greater in STM of CAR and ARG compared with CON piglets. These results suggest that ARG and CAR supplements were beneficial for muscle maturation whereas findings on phenotypic traits were rather unsystematic.

Handling Associated with Drenching Does Not Impact Survival and General Health of Low Birth Weight Piglets

“…NEFA and urea levels were both lower at two weeks after weaning compared to immediately after the drenching period. Plausible explanations for these findings could be that neonatal piglets have a higher demand for fatty acid mobilization and gluconeogenesis in response to an increased energy demand, as suggested by Madsen et al [24], and the high amount of fats that can be found in the sow's milk [62]. Since this study showed no effect of drenching on the protein or lipid metabolism, nor any increase (or decrease) in glucose levels, and high (or low) blood glucose concentrations are correlated to the chance of survival [49], it can be assumed that drenching did not impose a significant threat on the pigs' survival chances.…”

“…In order for LBW piglets to acquire an adequate amount of energy and nutrients, farmers are often suggested to drench them with milk replacer, colostrum or enriched formula [21,23,24,37,38]. However, supplementing piglets via drenching implies chasing, picking up, restraining and drenching the animals while they are often agitated or scared.…”

“…Another potential intervention that might benefit LBW piglets' survival is supplementary feeding to provide extra energy [20,21] or bioactive substances (colostrum, oligosaccharides, antioxidants, etc.) [22][23][24][25][26]. Piglets can be supplemented with (enriched) milk replacer or colostrum by providing a plastic dish, a bowl or a milk bar in the farrowing box [22,27].…”

Basic mechanisms of the regulation of L‐carnitine status in monogastrics and efficacy of L‐carnitine as a feed additive in pigs and poultry

“…It is therefore likely that even the control piglets received an amount of L‐carnitine via the milk replacer sufficient to facilitate all L‐carnitine‐dependent functions in intermediary metabolism under the assumption that endogenous L‐carnitine biosynthesis may be limited in low birth‐weight piglets. In another study of the same group with an identical experimental design but a slightly lower L‐carnitine dose (400 mg/piglet and day), L‐carnitine supplementation also failed to significantly improve growth performance, semitendinosus muscle weight and myofibre size of low birth‐weight piglets ( n = 30, female and castrated from Swiss Large White sows) reared with a mainly cow milk product‐based milk replacer from day 7 to 28 of age (Madsen, Mueller et al., ). It is likely that the same reason as in the study before (Madsen, Seoni et al., ) accounts for the lack of effect of supplemental L‐carnitine.…”

Effect of dietary l-carnitine supplementation to sows during gestation and/or lactation on sow productivity, muscle maturation and lifetime growth in progeny from large litters

“…Enzyme activity analysis in the semitendinosus muscle. To characterise the citric acid cycle activity, lipid oxidation and glycolytic capacity, activities of citrate synthase (CS; EC 4.1.3.7), β-hydroxyacyl-CoA dehydrogenase (HAD; EC 1.1.1.35) and lactate dehydrogenase (LDH; EC 1.1.1.27), respectively, were measured in the STM d and STM l as previously described by Madsen et al (25) . In brief, protein was extracted from 100 μg of muscle samples that were stored at −80°C.…”