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Behavior and peripheral amine concentrations in relation to ractopamine feeding, sex, and social rank of finishing pigs
Posted in: Production, Welfare by admin on August 5, 2011 | No Comments
Aggression can impair productivity and well-being. The association between aggression in finishing pigs and the feed additive ractopamine (RAC), a β-adrenoreceptor agonist, is unknown and warrants further investigation. Our goal was to examine behavioral activity, including aggression, in the home pen and concentrations of peripheral amines in barrows and gilts, taking into account diet (RAC) and social rank. Sixty-four finishing pigs, housed in pens of 4 by sex, were fed either a control (CTL) or RAC-added (5 mg/ kg for 2 wk plus 10 mg/kg for another 2 wk) diet. The top dominant and bottom subordinate pigs in each pen were determined at mixing (2 wk pretrial). The behavior of all pigs was recorded continuously during the pretrial week (baseline) and for the following 4 wk. These behavioral data were used to evaluate home pen aggression, including the number of agonistic interactions (AINX) and constituent aggressive actions, during a 3-h period (0800 to 1100 h) once per week and their change in relation to the baseline. Time-budget behaviors and postures were analyzed over eight 24-h periods (2 d/wk) using 10-min instantaneous scan sampling that focused on only the dominant and subordinate pigs in each pen. These 2 pigs were also subjected to blood collection once per week during the trial to determine concentrations of dopamine, norepinephrine, epinephrine, and serotonin (5-HT) using HPLC. Gilts performed more bites and total actions per AINX than barrows, and RAC-fed gilts increased bites and pursuits, whereas these behaviors decreased compared with baseline values in all other subgroups. Gilts fed RAC increased the total number actions per AINX, whereas the occurrence of AINX decreased for all subgroups. Overall, RAC-fed pigs were more behaviorally active, spending more time alert, bar biting, and sham chewing compared with CTL pigs. The dominant RAC-fed pigs tended to have the greatest norepinephrine concentrations among the tested subgroups. Dominant barrows had greater epinephrine concentrations than subordinate barrows. The RAC-fed gilts tended to have lesser 5-HT concentrations than CTL gilts, whereas concentrations were similar in barrows. Greater activity and the increase in oral-related behaviors observed in RAC-fed pigs may be mediated by the increase in arousal caused by RAC. Intensified aggression in gilts, especially when fed RAC, may be linked to reduced central 5-HT and greater noradrenergic activity, and further research on brain neurotransmitters in gilts is needed.
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Aggressiveness and brain amine concentration in dominant and subordinate finishing pigs fed the β-adrenoreceptor agonist ractopamine
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Under farm conditions, aggression related to the formation of social hierarchy and competition for resources can be a major problem because of associated injuries, social stress, and carcass losses. Any factor that may affect the regulation and amount of aggression within a farmed system, for instance, feeding the β-adrenoreceptor agonist ractopamine (RAC), is therefore worthy of investigation. The objectives of this study were to assess the effects of the widely used swine feed additive RAC, considering also the effects of sex and social rank on aggressiveness and concentrations of brain amines, neurotransmitters essential for controlling aggression, in finishing pigs. Thirty-two barrows and 32 gilts (4 pigs/pen by sex) were fed either a control diet or a diet with RAC (Paylean, Elanco Animal Health, Greenfield, IN) added (5 mg/kg for 2 wk, followed by 10 mg/kg for 2 wk). The top dominant and bottom subordinate pigs (16 pigs/sex) in each pen were determined after mixing by a 36-h period of continuous behavioral observation. These pigs were then subjected to resident-intruder tests (maximum 300 s) during the feeding trial to measure aggressiveness. At the end of wk 4, the amygdala, frontal cortex, hypothalamus, and raphe nuclei were dissected and analyzed for concentrations of dopamine (DA); serotonin (5-HT); their metabolites 3,4-dihydroxyphenyl acetic acid (DOPAC) and homovanillic acid, and 5-hydroxyindoleacetic acid (5-HIAA), respectively; norepinephrine; and epinephrine using HPLC. Ractopamine-fed gilts performed more attacks during the first 30 s of testing than pigs in all other subgroups. By the end of the resident-intruder test (300 s), the dominant control gilts and barrows, and both dominant and subordinate RAC-fed gilts performed the greatest percentage of attacks. Gilts had decreased norepinephrine and DOPAC concentrations in the amygdala and frontal cortex, and when fed RAC, gilts also had the least 5-HIAA concentration and greatest DA turnover rate in the amygdala. The 5-HT concentration was less in the frontal cortex of gilts compared with barrows and in the raphe nuclei (single site for brain 5-HT synthesis) of dominant gilts. Ractopamine may be affecting aggressive behavior through indirect action on central regulatory mechanisms such as the DA system. The aggressive pattern observed in the tested pigs, especially in gilts, is likely linked to brain monoamine profiling of a deficient serotonergic system in the raphe nuclei, amygdala, and frontal cortex, and enhanced DA metabolism in the amygdala, brain areas vital for aggression regulation.
For more information the full article can be found at http://jas.fass.org/
Effect of dietary organic and inorganic micromineral source and level on sow body, liver, colostrum, mature milk, and progeny mineral compositions over six parities
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A sow study evaluated the effects of 2 dietary micromineral sources (organic or inorganic) and 3 dietary mineral levels [NRC, industry (IND), and IND + Ca:P] with selected sows killed at parities 1, 2, 4, and 6. Three sows per treatment group were killed at weaning (total = 68), and their body and liver, 72 colostrum and milk samples (17 d), 69 full-term stillborn pigs and their livers, and 32 pigs at weaning were analyzed for minerals. Tissue and milk samples from the sows were analyzed as a 2 × 3 × 4 factorial arrangement of treatments in a completely randomized design (CRD) with 3 replicates per treatment. Full-term stillborn pig mineral compositions were determined at parities 1, 3, and 5 and evaluated as a 2 × 3 × 3 factorial arrangement of treatments in a CRD with 3 replicates per treatment. Weanling pigs from parity 6 sows were analyzed as a 2 × 3 factorial in a CRD. Sow and pig mineral compositions are reported on an equivalent empty BW and kilograms of liver weight basis. The results indicated that sow body macromineral contents were not affected by dietary micromineral source or level or when the diets contained added Ca and P. Sow body Se increased when dietary organic microminerals increased from the NRC to the IND level, resulting in a source × level interaction, but there was no increase in those sows fed inorganic microminerals. There were increases in Cu and Se as levels increased from NRC to the IND, and there were increases in Cu and Zn when the IND + Ca:P diet was fed compared with feeding the IND diet. Increases in sow liver Cu, Se, and Zn occurred as microminerals increased from the NRC to the IND level. As parity advanced, there were cubic increases in sow body Cu, Fe, and Se, but a quadratic increase in Zn. There was no clear effect of sow dietary treatments on full-term stillborn pig or liver micromineral contents, except Se. There was a greater pig body Se content when sows were fed organic microminerals at the greater level, resulting in a source × level interaction. Colostrum minerals were generally not affected by diet variables, except Se. Colostrum Se was greater when sows were fed the organic micromineral source than the inorganic source at the greater level, resulting in a source × level interaction. Milk Cu and Zn increased as dietary level increased. Milk Se was increased when organic Se was fed and when the micromineral level was increased. Weaned pig body Fe and Se were greater when organic microminerals were fed to the sow, whereas Mn and Zn increased when the IND level was fed. These results indicate that the dietary micromineral source and level had a minimal effect on sow body and liver mineral contents or in colostrum and pigs at birth, except Se, which was greater when the organic form was fed.
For more information the full article can be found at http://jas.fass.org/
Transfer of conjugated linoleic acid from sows to their offspring and its impact on the fatty acid profiles of plasma, muscle, and subcutaneous fat in piglets
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This experiment was conducted to determine if CLA could be transferred from sows to their offspring through the umbilical cord or milk. Eighteen pregnant Dalland sows of mixed parity were used in a completely randomized block design based on parity and BW. The sows were allotted to 1 of 3 groups and fed diets containing 0, 0.5, or 1.0% CLA during the last 50 d of gestation and throughout a 26-d lactation (n = 6). Umbilical cord blood was sampled at parturition. Colostrum and milk were collected from each sow on d 2 and 15 after farrowing. Samples of blood, backfat, and the LM were obtained from piglets at 2 and 26 d of age. Sow reproductive performance and piglet growth were not altered by CLA supplementation during the late gestation and lactation periods. The CLA supplementation of sow diets had an impact on the fatty acid profiles in colostrum and milk. Dietary CLA increased the concentrations of total SFA (linear and quadratic), but reduced the total MUFA in the colostrum (linear and quadratic). Although dietary CLA increased the concentrations of total SFA (quadratic), it had no influence on total MUFA concentrations in the milk. In addition, feeding sows diets supplemented with CLA resulted in increases (linear and quadratic) in the CLA content of plasma, backfat, and the LM in their offspring. However, trans-10, cis-12–18:2, rather than cis-9, trans-11–18:2, was detected in the umbilical cord blood, which indicates that CLA may be transported from the sow to the fetus in an isomer-specific manner.
For more information the full article can be found at http://jas.fass.org/
Technical note: Efficient protocol for isolation of total ribonucleic acid from lyophilized fat and muscle pig samples
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Isolation of total RNA from frozen muscle and fat samples typically results in small yields due to the presence of connective tissue between muscle fibers, which impairs complete tissue homogenization, and the excess of fat and relatively small cellularity of adipose tissue. Meat quality studies involve determination of fatty acid composition and content from muscle and subcutaneous fat samples, a process that may produce an excess of lyophilized tissue samples. The purpose of this work was to investigate the stability of total RNA in lyophilized tissue samples generated during the routine detection of fatty acid content of pig muscle and fat tissues, stored at room temperature or at −20°C. The protocol described here results in increased yields of total RNA from freeze-dried samples stored at −20°C, which facilitates the homogenization step. The isolated RNA is suitable for common gene expression techniques such as final point and quantitative reverse transcription-PCR.
For more information the full article can be found at http://jas.fass.org/
Influence of the inclusion of cooked cereals and pea starch in diets based on soy or pea protein concentrate on nutrient digestibility and performance of young pigs
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An experiment was conducted to compare different dietary vegetable sources of starch and protein on the coefficient of apparent total tract digestibility (CATTD) of energy and nutrients and performance of piglets from 29 to 60 d of age. The experiment was completely randomized with 6 treatments arranged factorially with 3 sources of starch (cooked-flaked corn, cooked-flaked rice, and pea starch) and 2 sources of protein [soy protein concentrate (SPC) and pea protein concentrate (PPC)]. The pea starch and the PPC used were obtained by dehulling and grinding pea seeds to a mean particle size of 30 μm. Each treatment was replicated 6 times (6 pigs per pen). For the entire experiment, piglets fed cooked rice had greater ADG than piglets fed pea starch with piglets fed cooked corn being intermediate (471, 403, and 430 g/d, respectively). Protein source did not have any effect on piglet performance. The CATTD of DM, OM, and GE were greater for diets based on cooked rice than diets based on cooked corn with diets based on pea starch being intermediate. Crude protein digestibility was not affected by source of starch but was greater for the diets based on SPC than for diets based on PPC (0.836 vs. 0.821). Protein source did not affect the digestibility of any of the other dietary components. It is concluded that cooked rice is an energy source of choice in diets for young pigs. The inclusion of PPC in the diet reduced protein digestibility but had no effects on energy digestibility or piglet performance. Therefore, the finely ground starch and protein fractions of peas can be used in substitution of cooked corn or SPC, respectively, in diets for young pigs.
For more information the full article can be found at http://jas.fass.org/
A low-fat liquid diet increases protein accretion and alters cellular signaling for protein synthesis in 10-day-old pigs
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Previous research showed that neonatal pigs respond to decreases in energy density of liquid diets with increased feed intake, resulting in similar performance to pigs fed a more energy-dense diet. The objective of this experiment was to determine whether a high- (25%, HF) or low-fat (2%, LF) liquid diet would affect nutrient accretion rate and select proteins involved in energy homeostasis and protein synthesis in early weaned pigs. Ninety-six pigs, with an initial BW of 3,637 g, were weaned from the sow at 10 d of age and utilized in a randomized complete block design. Pigs were blocked by BW and then assigned to pens (8 pigs/pen). Diets were formulated to provide a constant AA:ME ratio and were fed for 10 d. Pigs were killed at 10, 15, and 20 d of age, at which time blood and LM were collected, and carcasses were prepared for body composition analysis. Blood was analyzed for plasma urea nitrogen (PUN) and NEFA. Longissimus dorsi was analyzed via western immunoblot for mammalian target of rapamycin (mTOR) and adenosine 5′ monophosphate-activated protein kinase (AMPK) phosphorylation. Pigs gained 347g/d, which resulted in an ending BW of 6,858g, regardless of dietary treatment. Pigs fed the LF diet consumed 25% more milk than pigs fed the HF diet (2,853 vs. 2,269 g dry feed・pen−1・d−1), which resulted in similar calculated ME intakes between dietary treatments (9.9 vs. 10.5 Mcal・pen−1・d−1). Feed conversion (G:F) was 24% greater in HF-fed compared with LF-fed pigs. Circulating NEFA (40 vs. 138 μEq/L) and PUN (3.0 vs. 17.7 mM) concentrations were less in LF pigs compared with HF pigs after 10 d of dietary treatments. Pigs consuming the LF diet had a 21% increase in protein accretion (50.5 vs. 61.2 g/d) and a 71% reduced lipid accretion rate (28.8 vs. 8.3g/d). Phosphorylation of AMPK was 29% less in LF pigs compared with HF pigs, whereas mTOR phosphorylation was increased by 37% in LF pigs. We conclude that feeding a LF liquid diet to pigs weaned from the sow at 10 d of age increases feed intake to regulate energy intake while maintaining growth performance. In addition, 10-d-old pigs consuming a liquid LF diet have increased protein deposition by a mechanism mediated through AMPK and mTOR.
For more information the full article can be found at http://jas.fass.org/
Genetic parameters for intramuscular fatty acid composition and metabolism in pigs
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The aim of this study was to estimate genetic parameters for pork intramuscular fatty acid (FA) composition and indices for desaturase and elongase activities involved in n-3 and n-6 PUFA metabolism. The LM of 437 slaughter pigs was analyzed for FA composition (expressed as g/100 g of FA). Indices for enzyme activities were calculated from product to precursor FA ratios. Genetic parameters were estimated with single- and multi-trait animal models. The total FA content, reflecting the intramuscular fat content, was either included or not in the model. Results from the models without total FA content showed relatively high heritability estimates, generally above 0.50, for the proportion of the most important MUFA and PUFA, compared with much smaller values for the SFA. When total FA content was included in the models, heritability values decreased for most individual FA and for all sums of FA groups, except for C18:0, C18:3n-6, and C18:3n-3. Heritability estimates for the ratios C20:4n-6/C18:2n-6 and C22:6n-3/C18:3n-3, reflecting the overall conversion in the n-6 and n-3 PUFA pathway, respectively, were 0.29 and 0.35, respectively, with total FA content in the model and increased to 0.38 and 0.49, respectively, if total FA content was not in the model. Heritabilities for other more specific indices were of the same order. Genetic correlations between PUFA proportions and indices for enzyme activities with ADG were mostly negative, whereas the correlations with carcass lean meat percentage were mostly positive. It was concluded that there is meaningful genetic variation for long-chain PUFA metabolism that is only partly dependent on the carcass and muscle fat content. This may allow selection for improved FA composition of pork.
For more information the full article can be found at http://jas.fass.org/
Identification and expression analysis of connexin-45 and connexin-60 as major connexins in porcine oocytes
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During mammalian oogenesis, intercellular communication between oocytes and the surrounding follicle cells through gap junction channels is crucial for oocyte development and maturation. The channel properties of gap junctions may be affected by the composition or combination of connexins, the expression of which is regulated by gonadotropins and other factors. Thus, identification and expression analysis of connexin genes in oocytes and follicle cells will help us to better understand how oogenesis and folliculogenesis are regulated in a species-specific manner in mammals. We previously reported the spatiotemporal expression of multiple connexin genes in porcine follicle cells. Here, we searched for connexin genes specifically expressed in porcine oocytes that may be involved in the formation of gap junctions between oocytes and follicle cells. To achieve this, we constructed an oocyte-specific cDNA library to identify which connexin genes are expressed in these cells and found that gap junction protein, alpha 10, which encodes connexin-60, and a porcine ortholog of mouse gap junction protein, gamma 1 encoding connexin- 45, are the major connexins expressed in porcine oocytes during folliculogenesis. Immunostaining and in situ hybridization of sectioned porcine ovaries confirmed oocyte expression of these genes at 3 different stages of ovary development. Furthermore, their gap junction channel activity was assessed using a heterologous cell system. However, gap junction protein, alpha 4, which encodes connexin-37 and is expressed in the oocytes of several other mammals, was undetectable. We demonstrate that there is diversity in the connexin genes expressed in mammalian oocytes, and hence in the gap junctions connecting oocytes and cumulus cells.
For more information the full article can be found at http://jas.fass.org/
Comparison of dried whey permeate and a carbohydrate product in diets for nursery pigs
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Three experiments were conducted to compare dried whey permeate (DWP; 80% lactose) and a carbohydrate product (CHO; 40% lactose, 30% sucrose, and 10% glucose) for nursery pigs. Pigs were fed in a 3-phase feeding program, and diets contained 1.6, 1.4, and 1.2% total Lys for phases 1 (d 0 to 7), 2 (d 7 to 21), and 3 (21 to 28). Dietary treatments included 1) control (no lactose), 2) low level of DWP, 3) high level of DWP, 4) low level of CHO, and 5) high level of CHO. In Exp. 1 (4 reps of 4 pigs per pen; initial BW = 7 kg and 23 d of age), the low and high levels used for each source in each phase were phase 1 (12.5 and 25%), phase 2 (10 and 20%), and phase 3 (6 and 12%). In Exp. 2 (6 reps of 5 pigs per pen; initial BW = 8 kg and 26 d of age) and 3 (4 reps of 4 pigs per pen; initial BW = 6 kg and 21 d of age), the inclusion levels were phase 1 (6 and 12%), phase 2 (3 and 6%), and phase 3 (common diet with no lactose). In Exp. 1, pigs fed diets with DWP or CHO had increased ADG and ADFI compared with pigs fed the control diet during phase 1. Gain:feed was reduced for pigs fed diets with CHO. During phases 2, 3, and overall, ADG, ADFI, and G:F were not affected by diet. In Exp. 2, pigs fed diets with CHO had increased ADG and ADFI compared with pigs fed the control diet during phases 1 and 2. Pigs fed diets with CHO had increased ADFI in phases 1 and 2 and increased ADG in phase 2 compared with pigs fed diets with DWP. Overall, pigs fed diets with DWP and CHO had increased ADFI compared with pigs fed the control diet, but ADG was increased for pigs fed diets with CHO. In Exp. 3, ADG, ADFI, and G:F were not affected by DWP or CHO during phase 1. Daily BW gain was increased for pigs fed diets with DWP or CHO during phase 2 compared with pigs fed the control diet. Overall, ADG was increased for pigs fed diets with DWP, but ADFI and G:F were not affected. Results from the combined data of Exp. 2 and 3, indicated that overall ADG and ADFI were increased in pigs fed diets with DWP or CHO compared with pigs fed the control diet. These data suggest that DWP or CHO improve growth performance of weanling pigs.
For more information the full article can be found at http://jas.fass.org/