Prenatal stress effects on pig development and response to weaning

Posted in: Welfare by admin on January 1, 2008 | No Comments

Prenatal stress, the stress imposed on a pregnant dam that may influence her subsequent offspring, has been shown to have profound effects on behavior and physiology of many species, including swine (Haussmann et al., 2000; Tuchscherer et al., 2002; Kanitz et al., 2003; Otten et al., 2004). Research in our laboratory (Haussmann et al., 2000) has shown that prenatal stress, including restraint and ACTH injection of the sow, caused offspring to have altered neurohormones and adrenal gland morphology, greater plasma cortisol in response to stress, and less ability to heal a wound. Similarly, another research team has recently published a series of papers (Tuchscherer et al., 2002; Kanitz et al., 2003; Otten et al., 2004) in which they used either 5-min restraint stress or exogenous ACTH administration during sow gestation to cause prenatal stress. Those researchers found that prenatal stress impaired the immune function, increased the maximum binding capacity of glucocorticoids receptors in the central nervous system immediately after birth, and caused an increase in fetal cortisol that may be the mechanism by which prenatal stress causes its effects. Kranendonk et al. (2005) recently reported that oral administration of glucocorticoids to pregnant sows might prove to be a useful model for studying its deleterious effects. The phenomenon of prenatal stress demands our complete understanding to optimize both welfare and productivity in farm animals because prenatal stress can affect both the physiology and behavior of animals and it affects a wide array of species. Thus, to further explore the phenomenon of prenatal stress and its effects in swine, we subjected gestating sows to i.v. injections of ACTH (1 IU/kg of BW), exposure to rough handling for 10 min (Rough), or no treatment (Control) once a week during d 42 to 77 of gestation. To determine the plasma cortisol response to treatments, blood (5 mL) was collected from 30 sows after treatment administration. To conduct the prenatal stress study, a separate group of 56 sows was used in 1 of 4 replicates. At birth, production data were collected for each litter, including birth weight, number born, anogenital distance, and pig viability. At weaning, pigs were blocked by BW and sex, and placed in a nursery pen of 6 pigs, with 2 pigs from each treatment group. To assess the effect of treatments on cortisol, corticosteroid- binding globulin (CBG), and hematological cell profiles, blood was collected every other day for 10 d after weaning. Application of treatments caused plasma cortisol concentrations to be greatest in ACTH sows compared with Control sows (P < 0.001), with Rough sows having intermediate values (P = 0.07). Treatments did not affect the number of pigs born, number of stillborn, or pig viability (P > 0.40). The ratio of cortisol to CBG did not differ between treatments (P = 0.09). Hematological variables did not differ between treatments (P > 0.19). Pigs born to ACTH sows had a smaller anogenital distance compared with controls (P < 0.03), with pigs from Rough sows being intermediate. Our data indicate that swine exposed to prenatal stress (ACTH injection) can have alterations in sexual morphology without effects on growth or the immune cell populations measured in this study.

For more information the full article can be found at http://jas.fass.org/

The ear skin temperature as an indicator of the thermal comfort of pigs

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The aim of the study was to investigate the relationship between the ear skin temperature and the behaviour of pigs. Fifty-four pigs weighing 75 ± 5 kg were used in three replications (18 pigs per replication) and housed in pens (six pigs per pen) in a controlled climate facility. The room temperature was changed by 2 °C from 18 °C down to 10 °C and up again to 22 °C. The ear skin temperature (EST) was continuously recorded and the activity, lying posture, location and contact with pen mates were scored by 12 min scan sampling for 24 h at the set point temperatures 18 °C, 10 °C and 22 °C. A diurnal rhythm in the EST, the posture and the lying behaviour was found. The EST was highest at night and lowest in the afternoon. During night the pigs had more physical contact to pen mates than during day time. For all three
set point temperatures the predominant lying position during the night was the fully recumbent position. The room temperature affected the lying behaviour and the EST. With decreasing room temperature the pigs increased their contact to pen mates and fewer pigs were observed lying in the fully recumbent position. The EST decreased with decreasing room temperature, and the range in the EST’s at the three set point temperatures was larger during day than night (4 °C versus 2 °C). The results indicate that pigs adjust their behaviour to a higher EST when resting than when they are active, and they use behavioural adjustment (e.g. increased/decreased contact to pen mates) to bring their skin temperature into a preferred interval.

For more information the full article can be found at http://journals.elsevierhealth.com/periodicals/applan/issues

Livestock industry tackles new era in animal welfare

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New trends, the latest research and leading strategies on farm animal welfare. All were featured at the 2008 Livestock Care Conference in Red Deer, Alberta. The annual conference, featuring international heavyweights in the field, is hosted by Alberta Farm Animal Care (AFAC), a partnership of Alberta’s major livestock groups with a mandate to promote responsible, humane animal care within the livestock industry. A list is provided regarding the feature articles presented at the conference.

A regional evaluation of injections of high levels of vitamin A on reproductive performance of sows

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A regional study involving 443 litters
from 182 sows was conducted at 5 cooperating experiment
stations to determine the effects of an i.m. injection
of vitamin A at weaning and breeding on subsequent
litter size of sows. The results of this
regional project demonstrated that injection of high
doses of vitamin A in young sows at weaning and breeding
improves the subsequent number of pigs born and
weaned per litter, indicating that vitamin A requirements
for maximal performance may vary with age.

Influence of dietary phosphorus concentration on the digestibility of phosphorus in monocalcium phosphate by growing pigs

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This study was done to determine if the dietary inclusion rate of phosphorus influences the digestibility of it. The results concluded that the digestibility and absorption of phosphorus from monocalcium
phosphate was not influenced by the dietary concentration of phosphorus.

Effects of chito-oligosaccharide supplementation on the growth performance, nutrient digestibility, intestinal morphology, and fecal shedding of Escherichia coli and Lactobacillus in weaning pigs

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50 weaning pigs were selected to investigate the effect of dietary chito-oligosaccharide (COS) supplementation on growth performance, fecal shedding of Escherichia coli and Lactobacillus, apparent digestibility and small intestinal morphology. The results indicated that dietary supplementation of COS at 100 and 200 mg/kg enhanced growth performance by increasing apparent digestibility, decreasing the incidence of diarrhea and improving small intestinal morphology.

Fasting regulates the expression of adiponectin receptors in young growing pigs

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Adiponectin is an adipocyte-derived
hormone that can improve insulin sensitivity. Its functions
in regulating glucose utilization and fatty acid
metabolism in mammals are mediated by 2 subtypes
of adiponectin receptors (AdipoR1 and AdipoR2). This
study was conducted to determine the effect of fasting
on the expression of adiponectin and its receptors.
The expression of adiponectin was not affected in s.c.
adipose tissue, but adiponectin expression increased in
visceral adipose tissue after fasting. In contrast, expression
of both AdipoR mRNA was increased in the liver
and s.c. adipose tissue of 24-h-fasted pigs compared
with fed pigs, but the mRNA in muscle and visceral
adipose tissue was not affected by fasting. A third putative
adiponectin receptor, T-cadherin, was cloned and
the mRNA expression was determined. T-Cadherin has
been recognized to act as a vascular adiponectin receptor
in vascular endothelial and smooth muscle cells. Our
data showed that the expression of T-cadherin was decreased
in the muscle of fasted pigs, suggesting that the
expression of T-cadherin can be regulated by feeding
status. In summary, in young pigs, adiponectin mRNA
was up-regulated by fasting in visceral, but not s.c.,
adipose tissue, whereas AdipoR1 and AdipoR2 mRNA
were increased in s.c., but not visceral, adipose tissue.
The adiponectin receptor, T-cadherin, was expressed in
s.c. and visceral adipose tissue and in muscle, but only
muscle mRNA expression was decreased by fasting.

InraPorc: A model and decision support tool for the nutrition of sows

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The process of reproduction, from conception to weaning, can be considered as directed to buffer the developing progeny from nutritional distress (Oldham, 1991) and involves both homeostatic and homeorhetic controls of nutrient partitioning (Bauman and Currie, 1980). Reproductive problems, which may result in the reduction of sows productivity or early culling, are often related to extreme variations in body reserves (Dourmad et al., 1994), although body reserves should be considered more as an indicator of the risk for rather than as the real cause of problems. During pregnancy, sufficient body reserves must be built to compensate for the eventual nutritional deficit that may occur in the following lactation. However, these reserves should not be excessive in order to avoid the occurrence of farrowing problems that are typical for fat sows, or to impair feed intake after farrowing. During lactation, it is recommended to adapt nutritional supplies to requirements in order to maximise milk production and piglet’s growth, and minimize reproductive problems of sows after weaning. Consequently, nutritional supplies to sows must be adapted to maintain body reserves in optimal condition all along their productive life and optimise their reproductive performance. On farm, this requires a precise adjustment of the feeding level and the feed composition according to the performance of sows but also to housing conditions, which may affect nutrient utilisation and voluntary feed intake. Experimental results obtained during the last 20 years on energy and amino acid utilization by the pregnant or lactating sow allow improvements in the determination of nutritional requirements according to a target performance (factorial approach), and to predict the response of the animal to nutrient supplies (modelling). Compared to growing pigs, only a few models have been published for sows (Williams et al., 1985; Dourmad, 1987; Pomar et al., 1991; Pettigrew et al., 1992; NRC, 1998), and most of these were research models. In this project, we have integrated the available information on nutrient utilisation by sows to build a decision support tool allowing a global approach to understanding sow nutrition and the associated performance. This decision support tool includes a simulation model that represents on a daily basis (dynamic) the utilisation of key nutrient pools (mechanistic) for a given sow (deterministic). The end-users of these decision support tools are mainly nutritionists involved in pig production and teachers and students in animal nutrition. The aim of the present paper is to describe the basis and the main principles of this tool, which is also available for download at http://www.rennes.inra.fr/inraporc/(INRA, 2006). The sow is represented as different compartments that change over the reproductive cycle. Nutrient flows considered are those of energy and digestible amino acids. Nutrients are used with the highest priority for maintenance and uterine growth or milk production. Subsequently, deposition and/or mobilization of body proteins and lipids are determined and used for estimating the changes in body weight and backfat thickness of the sow. A decision support tool was built from the set of equations given, with additional modules to describe animal’s characteristics and adjust some model parameters to account for variations in genotypes and performance. This tool can be used to determine energy and amino acids requirements of sows according to production objectives, or to predict body composition changes according to a given feeding strategy.

Frequency of the HAL-1843 mutation of the ryanodine receptor gene in dead and nonambulatory-noninjured pigs on arrival at the packing plant

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Four Midwestern packing plants (designated as plants A, B, C, and D) were visited on 53 occasions, and tissue samples were collected postmortem from a total of 2,019 pigs to determine the frequency of the HAL-1843 mutation of the ryanodine receptor gene in dead (DOA), nonambulatory-noninjured (NANI), and normal animals. The mutation was present in all 3 classes of pig. There was a greater frequency of carriers in DOA animals than in the normal or NANI pigs. The 55 pigs that had at least 1 copy of the mutation came from 53 farms; therefore, the mutation was relatively widespread, being present in approximately 11% of the farms sampled. Therefore the data shows that the HAL-1843 mutation is still present in US commercial pig populations, it is low in frequency and therefore not a major cause of transport losses.

A Neonatal Swine Model of Allergy Induced by the Major Food Allergen Chicken Ovomucoid (Gal d 1)

Posted in: Ontario Pork, Pork Insight Articles by admin on December 14, 2007 | No Comments

Food allergy is a serious health problem for which a validated outbred large animal model would be useful in comparative investigations of immunopathogenesis and treatment and in testing hypotheses relevant to complex
host-environmental interactions in predisposition to and expression of food allergy. Objective: To establish a neonatal
swine model of IgE-mediated allergy to the egg protein ovomucoid (Ovm) that may mimic human allergy. In order to induce Ovm sensitivity, piglets at days 14, 21 and 35 of age were sensitized by intraperitoneal injection of 100  g of crude Ovm and cholera toxin (50, 25 or 10  g). Controls received 50  g of cholera toxin in phosphate-buffered saline. The animals were challenged orally on day 46 with a mixture of egg white and yoghurt. Outcomes were reported as direct skin tests, clinical signs, IgG-related antibody and passive cutaneous anaphylaxis. Results: Sensitized pigs developed immediate wheal and flare reactions, and after oral challenge, sensitized but not control animals displayed signs of allergic hypersensitivity. Serum IgG-related, Ovm-specific antibodies were detected only in the sensitized pigs and IgE-mediated antibody response to Ovm was confirmed by positive passive cutaneous anaphylaxis reactions induced by sera of sensitized but not by heat-treat-ed sera from Ovm-sensitized pigs or sera of unsensitized control pigs. The present results confirm induction of Ovm-specific allergy in pigs and provide opportunity to investigate allergic predisposition and immunopathogenesis of IgE-induced Ovm allergy using outbred neonatal swine. This may better simulate allergic disease in humans and allow investigation of candidate prophylactic and therapeutic approaches.