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Belly nosing is an abnormal behaviour pattern most commonly seen in early-weaned piglets. Because belly nosing resembles massaging the sow’s udder, it has been suggested that the behaviour is redirected suckling and may be associated with hunger or feeding motivation. The objective of this study was to determine the effect of feed restriction on the behaviour of newly weaned piglets. Eight groups of four piglets were fed ad libitum during weeks 1, 2 and 3 post-weaning (control), while treatment piglets (eight groups of four) were fed ad libitum during weeks 1 and 3, and feed restricted during week 2. During restriction, ad libitum intake from the previous day was determined from control groups (voluntary intake of 1.9 times maintenance energy requirement), averaged, and treatment piglets were provided with 65% of this amount (1.2 times maintenance energy requirement). While both groups continued to gain weight during the restriction period, weight gain was significantly lower for restricted piglets compared to controls (P < 0.05). Behaviour was observed on days 5, 7, 9, 12, 14, 17, and 20 post-weaning using a 5-min scan sampling method for 6 h/day. During the period of restriction, treatment piglets spent less time at the feeder (5.3 0.9%; controls, 8.3 0.6%, P < 0.05) and more time nosing and chewing at the pen (4.1 1.0%; controls 1.4 0.4%, P < 0.05) compared to controls. Mean percentage of time spent belly nosing was not statistically different (3.5 0.89%; controls 2.1 0.53%, P = 0.13), but the variation among piglets was significantly greater in treatment groups (P < 0.05) during the restriction period. During the post-restriction period, treatment piglets engaged in significantly more belly nosing behaviour (1.8 0.6%; controls, 0.5 0.2%, P < 0.05), while nosing and chewing at the pen was similar between the two groups. Feed restriction stimulated foraging-type behaviour directed at the pen during the period of restriction, and increased and altered the time course for belly nosing, but it did not elicit belly nosing in all pigs. Individual differences in response to feed restriction suggest that there is a causal relationship between low feed intake and belly nosing, but only in piglets with a predisposition for the behaviour. # 2007 Elsevier B.V. All rights reserved.

Bovine macrophages (BoMacs) were exposed to the following Penicillium mycotoxins (PM): citrinin (CIT), ochratoxin A (OTA), patulin (PAT), mycophenolic acid (MPA) and penicillic acid (PA). PM exposure at the concentration that inhibits proliferation by 25% (IC25) differentially for 24h altered the gene expression of various cytokines. OTA significantly induced IL-1α expression (p

Penicillium mycotoxins (PMs) are contaminants that are frequently found in grain or crop-based silage for animal feed. Previously, we have characterized the potential immunotoxicity of the following PMs: citrinin (CIT), ochratoxin A (OTA), patulin (PAT), mycophenolic acid (MPA), and penicillic acid (PA) by using a bovine macrophage cell line (BoMacs). In the present study, cell proliferation was used as a bioassay endpoint to evaluate the efficacy of a modified yeast cell wall extract (mYCW), for preventing PM toxicity under various in vitro conditions such as the following: pH (3, 5, 7), incubation time (1, 2, 4, 6 h), percentage of mYCW (0.05, 0.1, 0.2, 0.5, 1.0 %), and PM concentration. mYCW was most effective in preventing the toxicity of 12.88 and 25.8 μM OTA at pH 3.0 (p < 0.0001), regardless of incubation time (p < 0.0001) and the percentage of mYCW (p < 0.0001). An incubation time of 6 h (p < 0.05) or 0.5 and 1.0 % mYCW (p < 0.0001) significantly improved the efficacy of mYCW for preventing CIT toxicity. In contrast, 0.5 and 1.0 % of mYCW appeared to exacerbate the PAT toxicity (p < 0. 0001). This effect on PAT toxicity was constantly observed with higher PAT concentrations, and it reached significance at a concentration of 0.70 μM (p < 0.0001). mYCW had no effect on PA toxicity. These results suggest that mYCW may reduce OTA toxicity and, to some extent, CIT toxicity at pH 3.0. Although PAT toxicity was increased by mYCW treatment, PAT is readily degraded during heat treatment and may therefore be dealt with using other preventative measures.

Thirty-three paired indicator/nutrient dilution curves across the mammary glands of four cows were obtained after rapid injection of para-aminohippuric acid (PAH) plus glucose into the external iliac artery. For the measurement of extracellular volume and kinetics of nutrient uptake from indicator dilution curves, several models of solute dispersion and disappearance have been proposed. The Crone-Renkin models of exchange in a single capillary assume negligible washout of solutes from the extracellular space and do not describe entire dilution curves. The Goresky models include a distribution of capillary transit times to generate whole system outflow profiles but require two indicators to parametize extracellular behavior. A compartmental capillary, convolution integration model is proposed that uses one indicator to account for the extracellular behavior of the nutrient after a paired indicator/nutrient injection. With the use of an iterative approach to least squares, unique solutions for nonexchanging vessel transit time μ and its variance σ were obtained from all 33 PAH curves. The average of heterogeneous vascular transit times was approximated as 2σ = 8.5 s. The remainder of indicator dispersion was considered to be due to washout from a well-mixed compartment representing extracellular space that had an estimated volume of 5.5 liters or 24% of mammary gland weight. More than 99% of the variation in the time course of venous PAH concentration after rapid injection into the arterial supply of the mammary glands was explained in an unbiased manner by partitioning the organ into a heterogeneous nonexchanging vessel subsystem and a well-mixed compartmental capillary subsystem.

Initial rates of glucose entry into isolated bovine mammary epithelial cells display moderate degrees of asymmetry and cooperative interactions between export and import sites. The present study examined the hypothesis that these kinetic features are due to compartmentalization of intracellular glucose. Net uptake of 3- O-methyl-d-[1-3H]glucose (3-OMG) by isolated bovine mammary epithelial cells was measured at 37°C. The time course of 3-OMG net uptake was better fitted by a double-exponential equation than by a single- or triple-exponential equation. Compartmental analysis of the time course curve suggested that translocated 3-OMG is distributed into two compartments with fractional volumes of 32.6 ± 5.7% and 67.4 ± 5.7%, respectively. The results support the view that glucose transport in bovine mammary epithelial cells is a multistep process consisting of two serial steps: fast, carrier-mediated, symmetric translocation of sugar across the cell plasma membrane into a small compartment and subsequent slow exchange of posttranslocated sugar between two intracellular compartments. A three-compartment model of this system successfully simulated the observed time course of 3-OMG net uptake and the observed dependence of unidirectional entry rates on intra- and extracellular 3-OMG concentrations. Simulations indicated that backflux of radiolabeled sugar from the small compartment to extracellular space during 15 s of incubation gives rise to the apparent asymmetry, trans-stimulation, and cooperativity of mammary glucose transport kinetics. The fixed-site carrier model overestimated the rate of glucose accumulation in cells, and its features can be accounted for by the compartmentalization of intracellular sugar.

Comparisons of growth for diploid and triploid full sibs from 20 families of Atlantic salmon (Salmo salar L.), ranging from 4 to 24 progeny/family, involved 628 individuals. Length and weight data, after approximately 75 weeks in seawater, indicated higher within and between family variances in triploids than in diploids. Regression analyses revealed that improvement of triploid populations might require measurements on triploid sibs of the diploid to be involved in reproduction.

In this study, the modulation of key enzymes involved in epigenetic regulation was assessed in immortalized bovine macrophages (BoMacs) following in vitro exposure to the following Penicillium mycotoxins: citrinin (CIT), ochratoxin A (OTA), patulin (PAT), mycophenolic acid (MPA), penicillic acid (PA), or a combination of one of the above with OTA at the concentration that inhibits BoMac proliferation by 25 % (IC25). Real-time PCR analysis of the genes coding DNA methyltransferases (DNMTs), histone demethylases (JMJD-3 and UTX), as well as the class-1 histone deacetylases (HDAC−1, −2, and −3) and histone acetylase (Bmi-1) was assessed following 6 h of mycotoxin exposure. A change in the expression of JMJD-3 as well as HDAC-3, MPA (p = 0.1) and PA (p = 0.08), by at least one of the treatments was observed at their respective IC25. The expression of JMJD-3 was significantly induced by PA, but synergistically suppressed by CIT + OTA. The combination of CIT + OTA also synergistically suppressed the expression of DNMT-3a and DNMT-3b. The combination of PAT + OTA reduced DNMT-3a expression, while PA + OTA reduced DNMT-3b expression. Lastly, MPA and PA slightly reduced HDAC-3 expression, while OTA in combination with CIT, PAT, MPA or PA synergistically suppressed HDAC-3 expression. The results of this study demonstrate that Penicillium mycotoxin exposure, specifically OTA and other mycotoxin combinations, can alter the expression of BoMac enzymes that are involved in epigenetic regulation. These findings suggest a potential novel regulatory mechanism by which mycotoxins can modulate macrophage function.