The aim of this study was to investigate the effect of two dietary treatments (liquid creep feed (LCF) and dry creep feed (DCF)) offered during the suckling period on feed disappearance, number of eaters, and intestinal enzymatic development at weaning in an on-farm study with 347 piglets. Piglets were allocated to either the DCF or LCF treatment from day 10 to day 24 postpartum for 9 h a day. Red ferric oxide (1%) was added to the diet to categorize piglets into eating categories (good eaters, moderate eaters, or non-eaters) via faecal swabs. At weaning, 40 piglets were sampled for intestinal enzymatic development. The LCF treatment increased the dry matter disappearance from day 10–18 (p < 0.001). The percentage of good eaters, moderate eaters and non-eaters did not differ between treatments (p > 0.05). The DCF pigs displayed greater average daily gain (ADG) pre-weaning (p = 0.024), and a greater body weight (BW) at day 61 (p < 0.001). The activity of lactase, maltase and sucrase in the proximal part of the small intestine were greatest (p < 0.001) in the DCF pigs.

The aim of this study was to evaluate whether the compensatory growth feeding strategy could be a suitable solution for overcoming the negative effects on growth, carcass composition and meat quality of low birth weight pigs. Forty-two Swiss Large White barrows from 21 litters were selected at weaning and categorized into either being light (L; > 0.8 and < 1.3 kg) or heavy (H; > 1.7 kg) birth weight pigs. From 27.8 kg BW, pigs were assigned within birth weight group to one of three feeding groups: AA: ad libitum access to the grower and finisher diet, RR: restricted access to the grower and finisher diet or RA: restricted access to the grower diet and ad libitum access to the finisher diet. At slaughter, the longissimus (LM) and semitendinosus (STM) muscles were removed from the right side of the carcass. Weight, girth and length of the STM and the LM area were determined after muscle excision. Carcass characteristics and meat quality traits were assessed. Using mATPase histochemistry, myofibre size and myofibre type distribution were determined in the LM and STM. Because of longer days on feed, total feed intake was greater (P < 0.01) and feed efficiency was lower (P < 0.01) in L than H barrows. Regardless of the birth weight group, AA and RA barrows grew faster (P < 0.05) than RR barrows. During the compensatory growth period, RA barrows grew faster (P < 0.05) than AA or RR barrows. Growth efficiency did not differ between RA and RR barrows but was greater (P < 0.05) compared with AA barrows. Carcasses of L barrows were fatter as indicated by the lower (P ⩽ ≤ 0.05) lean meat and greater (P ⩽ 0.02) omental and subcutaneous fat percentage. Lean meat percentage was lower (P ⩽ 0.05) in AA and RA than RR barrows. These differences caused by ad libitum feed access tended to be greater (feeding regime × birth weight group interaction; P < 0.08) in L than H barrows. In L barrows, slow oxidative, fast oxidative glycolytic and overall average myofibre size of the LM and the fast glycolytic myofibres and overall average myofibre size of the dark portion of the STM were larger (P ⩽ 0.03) than in H barrows. The study revealed that the compensatory growth feeding strategy was inadequate in overcoming the disadvantages of low birth weight.

BackgroundIntra-uterine crowding (IUC) observed in hyperprolific sows impairs myofiber hyperplasia and overall fetal growth. Arginine supplementation (ARG) in gestation diets has been shown to positively affect litter and muscle development. The study objective was to assess whether the effect of ARG on offspring characteristics, with special emphasis on myofiber hyperplasia, differs under IUC conditions from these responses, because in that situation growth retardation is particularly prevalent due to reduced fetal nutrient supply. Unilateral oviduct ligation (OL) was used as a model for an uncrowded and hyperprolificacy (IN) as a model for a crowded intra-uterine environment.MethodsFive OL and five IN sows were fed a diet supplemented daily with either 43 g l-alanine (Ctrl) or 25 g l-arginine from d 14 to 28 of gestation in a cross-over design (two periods: 5th and 6th parity). At farrowing, two male and two female offspring, respectively, with a low and intermediate birth weight (BtW) were selected. After euthanization, the Semitendinosus muscle (STM) was removed and weighed, and the light and dark portions (STMd and STMl) were prepared for myofiber histochemistry using ATPase staining and the entire STM for gene expression analysis of myogenesis-related genes using RT-qPCR. In addition, various organs were removed and weighed. Data were analyzed using the MIXED model in SYSTAT.ResultsNo effect of either IUC or dietary treatment was found in litter characteristics. Offspring of ARG sows displayed a greater muscle area in STM (P < 0.01) as a result of the greater myofiber hyperplasia (P < 0.01). The increase was more distinct in the STMl (P < 0.05) than in the STMd (P = 0.131). Offspring of OL sows were heavier at birth (P < 0.01), had a heavier STM (P < 0.05), liver (P < 0.01) and kidney (P < 0.05), but when expressed relative to birth weight, these differences were absent. In addition, IUC had an effect (P < 0.05) on the expression of one of the myogenesis-related genes investigated.ConclusionsIndependent from the extent of IUC, ARG improved BtW, muscle and organ weights and myofiber hyperplasia in offspring.

SummaryLightweight (LW) piglets from large litters display impaired growth performance compared with heavier littermates. This study investigated the growth performance and muscle development of early-weaned LW piglets (birthweight <1.2 kg) from large litters (17.3 ± 3.0 total born per litter), fed ad libitum a milk replacer supplemented with either l-carnitine (CAR) or l-arginine (ARG) from day 7 to day 28 of age. In total, 36 female and entire male Swiss Large White piglets, weaned on day 7 of age, were artificially reared in pairs in rescue decks. They were allocated to one of three dietary treatments: unsupplemented control (CON), 0.48 g l-carnitine·piglet ·day −1 (ARG). Milk replacer was prepared daily in a 1:4 powder-to-water ratio and fed ad libitum. Piglets were weighed at birth and on days 7, 14, 21 and 28.Feed intake was assessed daily. Piglets were euthanized on day 28. The entire semitendinosus muscle (STM) was collected, and organs were weighed. Subsequently, the STM was divided into the light (STM l ) and dark (STM d ) portion, and contractile and metabolic traits were analysed by ATP histochemistry, enzyme activities and gene expression. No differences in growth performance, organ and STM weight and on contractile traits were found between groups. A tendency (p < .10) for an elevated lipid oxidation enzyme activity in the STM l and STM d and greater (p < .05) phosphorylation of the mammalian target of rapamycin pathway in the STM l of CAR compared with CON piglets was found.Despite these metabolic responses, the lack of effect of CAR and ARG supplementation on growth performance suggests that providing the milk replacer ad libitum in combination with added CAR and ARG is insufficient for eliciting faster growth of LW piglets. K E Y W O R D Samino acid, artificial rearing, growth performance, litter size, milk replacer | INTRODUCTIONIncreased litter size, a large within-litter variation and decrease in the average birthweight (BtW) of the litter are all consequences of selection for hyperprolific sows in the commercial pig production (Rutherford et al., 2013). Simultaneously in such sows, milk yield and number of functioning teats does no longer correspond to the number of piglets in the litter (Andersen, Naevdal, & Boe, 2011). This compromises the growth of the piglets in a way that they are unable to reach their full potential (Harrell, Thomas, & Boyd, 1993). Furthermore, lightweight compared with the litter average (Quiniou, Dagorn, & Gaudré, 2002), where the main cause of death across all BtW categories is documented to be crushing by the sow (Edwards, 2002). However, it is argued that due to undernourishment, LW piglets reside for longer periods in close proximity of the sow, thereby increasing the risk of crushing (Weary, Pajor, Thompson, & Fraser, 1996). In this context, early artificial rearing by relocating excess piglets to rescue decks and feeding them on milk replacer will naturally remove their risk of being crushed by the sow. Applying milk replacer to early-weaned piglets has been sh...