I. J. Lean

The Influence of Piglet Birth Weight on Physical and Behavioural Development in Early Life

The objective of this study was to determine whether body weight at birth influences the physical and behavioural development of the neonatal pig. Sixteen sows and their litters were randomly allocated into four treatment groups. From the normal distribution curve of their birth weight, piglets were sub-divided into three groups: (1) low (<10th percentile) (2) normal (10–90th percentile) and (3) high (>90th percentile).To assess behavioural development, each litter was exposed to a ball placed in the creep area for a period of 1,800 s, and evaluated once over a 3-day period starting on either 5, 7, 14 or 21 days of postnatal life. Their response to, and interaction with, an object was used to calculate a numerical index of piglet behavioural development. Teat order was calculated following observations during consecutive suckling on days 11, 13 and 15 of life, and dominance hierarchy was assessed on day 12, 14 and 16. Individual body weight was recorded on days 0, 5, 7, 14 and 21 of postnatal life. Statistical differences between groups were analysed using general linear model, analysis of variance. Regression analyses were used to determine relationships between physical and behavioural development with teat order and dominance. There was a significant (p < 0.001) relationship between birth weight, growth performance and behavioural development. Behavioural developmental index (BDI) significantly improved (p < 0.001) with age and was also influenced by the day on which the ball was introduced (p < 0.01). Body weight on day 1 of the test was significantly (p < 0.001) correlated to BDI and age at test. Piglets demonstrating compensatory growth were more dominant and exhibited an improved behavioural developmental score than their slower growing littermates. In conclusion, compromised growth in utero can have a detrimental effect on the physical and behavioural development of the neonate. Animals with an enhanced developmental index in conjunction with a higher dominance value exhibited a improved neonatal growth performance.

Effect of type and timing of oil supplements to sows during pregnancy on the growth performance and endocrine profile of low and normal birth weight offspring.

Eighty-eight multiparous sows were used to evaluate whether type and timing of oil supplementation during gestation influences the incidence of low birth weight (LBW). Sows were allocated (eight per treatment) commercial sow pellets (3 kg/d; control diet) or an experimental diet consisting of control diet plus 10 % extra energy in the form of excess pellets, palm oil, olive oil (OO), sunflower oil (SO) or fish oil; experimental diets were fed during either the first half (G1) or second half (G2) of gestation. Growth performance and endocrine profile of LBW (<1.09 kg) and normal birth weight (NBW; 1.46-1.64 kg) offspring were compared. Maternal dietary supplementation altered the distribution curve for piglet birth weight. SOG1 sows had a greater proportion of LBW piglets (P<0.05), whilst it was reduced in the OOG1 group (P<0.05). Growth rate of LBW piglets was lower compared with their NBW siblings (P<0.05) when dietary supplementation was offered in G2 but were similar for G1. At birth, LBW offspring of supplemented animals possessed more fat compared with the control group (P<0.05); LBW offspring of control animals exhibited a more rapid decline in fat free mass/kg prior to weaning. Plasma metabolites and insulin concentrations were influenced by maternal diet and birth weight. In conclusion, maternal dietary supplementation altered the distribution of piglet birth weights and improved the energy status of LBW piglets. Supplementation with MUFA during G1 reduced the incidence of LBW, whereas PUFA had the reverse effect.

Effects of Lipid-Supplemented Total Parenteral Nutrition on Fatty Liver Disease in a Premature Neonatal Piglet Model

Background: Routine total parenteral nutrition (TPN) in neonatal care can result in hepatic dysfunction in 40–60% of patients, most commonly as fatty liver, but little work has been conducted on the underlying mechanisms causing hepatic dysfunction. Objective: To use a piglet model for the premature human neonate on TPN, supplemented with lipid emulsions, to investigate hepatic responses.Method:Piglets were delivered 2 days prematurely. Six control piglets were fed enterally (E), whilst twelve animals were maintained on TPN. TPN piglets received the standard TPN solution plus the lipid emulsion as either ClinOleic® (C, n = 6) or Intralipid® (I, n = 6). Hepatic lipid content and the fatty acid composition of liver triacylglyercol (TAG) as well as hepatic lipase (HL) activity were determined. Lipoprotein lipase (LPL) activity was measured in the liver, muscle and adipose tissue. The plasma concentrations of choline, bilirubin, TAG and non-esterified fatty acids (NEFA) were also measured. Results:Liver lipid was significantly increased in piglets on TPN and the tissue fatty acid profiles reflected the lipid emulsion. HL and LPL activities were reduced in liver but LPL increased in adipose tissue during TPN. Plasma concentrations of choline, bilirubin, TAG and NEFA were similar across the treatments. Conclusions:The results suggest fatty liver occurs in neonates receiving TPN and the source of the accumulated lipid appears to be the lipid emulsion used. The factors regulating lipase activity during TPN require further study. The piglet can be used as a model for neonatal TPN.

Effect of liquid feeding at different water-to-feed ratios on the growth performance of growing-finishing pigs

The study examined the growth performance of pigs offered liquid feed or dry feed on either a restricted or an ad libitum basis, and whether their growth performance was further influenced by the water-to-feed ratio. The study was split into two parts to enable unrestricted (trial 1; n = 64) and restricted (trial 2; n = 48) feeding to be compared. Male pigs were randomly allocated to six dietary treatment groups. A standard dry pellets diet (D) was offered either as: (i) unrestricted ration (UR); (ii) restricted ration (R); or D soaked in water at a feed-to-water ratio of (iii) 1 : 1.5 restricted (1 : 1.5 R); (iv) 1 : 3 unrestricted (1 : 3 UR); (v) 1 : 3 restricted (1 : 3 R); or (vi) 1 : 3 restricted with the addition of lactic acid to adjust the feed to pH 4 (1 : 3(4) R). Liquid feeding improved (P < 0.05) average daily live-weight gain (ADG) and lean tissue growth rate (LTGR) in the 1 : 3 UR compared with DUR but did not alter feed conversion ratio (FCR). Within the R groups, ADG were greater in all of the 1 : 3 diets, whereas feed intake, and hence FCR, was lower (P < 0.001) in these groups when offered the R ration. In conclusion, liquid feeding has a beneficial influence on the performance of modern porcine genotypes during the growth/finishing phase and this is further modulated by the water-to-feed ratio.

Percentile growth charts for biomedical studies using a porcine model.

Increasing rates of obesity and heart disease are compromising quality of life for a growing number of people. There is much research linking adult disease with the growth and development both in utero and during the first year of life. The pig is an ideal model for studying the origins of developmental programming. The objective of this paper was to construct percentile growth curves for the pig for use in biomedical studies. The body weight (BW) of pigs was recorded from birth to 150 days of age and their crown-to-rump length was measured over the neonatal period to enable the ponderal index (PI; kg/m3) to be calculated. Data were normalised and percentile curves were constructed using Coles lambda-mu-sigma (LMS) method for BW and PI. The construction of these percentile charts for use in biomedical research will allow a more detailed and precise tracking of growth and development of individual pigs under experimental conditions.

Effect of dietary supplementation of different oils during the first or second half of pregnancy on the glucose tolerance of the sow

Poor glucose tolerance may be an under-researched contributory factor in the high (10% to 20%) pre-weaning mortality rate observed in pigs. Insulin resistance commences at around week 12 of gestation in the sow, although there are conflicting reports in the literature about the extent to which insulin resistance is modulated by maternal diet. The aim of the study was to determine the effects of supplementing the maternal diet with different dietary oils during either the first half or the second half of gestation on the glucose tolerance of the sow. Sows were offered the control (C: n = 5) diet as pellets or the C diet plus 10% extra energy (n = 16 per group) derived from either: (i) extra pellets; (ii) palm oil; (iii) olive oil; (iv) sunflower oil; or (v) fish oil. Experimental diets were fed during either the first (G1) or second (G2) half of gestation. A glucose tolerance test (GTT) was conducted on day 108 of gestation by administering 0.5 g/kg glucose i.v. Blood samples were taken every 5 to 10 min for 90 min post administration. The change in body weight and backfat thickness during gestation was similar but both type and timing of dietary supplementation influenced litter size and weight. With the exception of the sunflower oil group, supplementing the maternal diet in G1 resulted in larger and heavier litters, particularly in mothers offered palm oil. Basal blood glucose concentrations tended to be more elevated in G1 than G2 groups, whilst plasma insulin concentrations were similar. Following a GTT, the adjusted area under the curve was greater in G1 compared to G2 sows, despite no differences in glucose clearance. Maternal diet appeared to influence the relationship between glucose curve characteristics following a GTT and litter outcome. In conclusion, the degree of insulin sensitivity can be altered by both the period during which maternal nutritional supplementation is offered and the fatty acid profile of the diet.

Intergenerational effects of birth weight on glucose tolerance and reproductive performance.

Women who were themselves small-for-gestational age (SGA) are at a greater risk of adulthood diseases such as non-insulin-dependent diabetes mellitus (NIDDM), and twice at risk of having an SGA baby themselves. The aim of this study was to examine the intergenerational pig. Low (L) and normal (N) birth weight female piglets were followed throughout their first pregnancy (generation 1 (G1)). After they had given birth, the growth and development of the lightest (l) and heaviest (n) female piglet from each litter were monitored until approximately 5 months of age (generation 2 (G2)). A glucose tolerance test (GTT) was conducted on G1 pig at 6 months of age and again during late pregnancy; a GTT was also conducted on G2 pigs at 4 months of age. G1 L offspring exhibited impaired glucose metabolism in later life compared to their G1 N sibling but in the next generation a similar scenario was only observed between l and n offspring born to G1 L mothers. Despite G1 L mothers showing greater glucose intolerance in late pregnancy and a decreased litter size, average piglet birth weight was reduced and there was also a large variation in litter weight; this suggests that they were, to some extent, prioritising their nutrient intake towards themselves rather than promoting their reproductive performance. There were numerous relationships between body shape at birth and glucose curve characteristics in later life, which can, to some extent, be used to predict neonatal outcome. In conclusion, intergenerational effects are partly seen in the pig. It is likely that some of the intergenerational influences may be masked due to the pig being a litter-bearing species.