Effects of Feeding Grains Naturally Contaminated with Fusarium Mycotoxins on Performance and Metabolism of Broiler Breeders

A study was conducted to investigate the effects of feeding grains naturally contaminated with Fusarium mycotoxins on performance and metabolism of broiler breeders. Forty-two 26-wk-old broiler breeder hens and nine 26-wk-old roosters were fed the following diets: (1) control, (2) contaminated grains, and (3) contaminated grains + 0.2% polymeric glucomannan mycotoxin adsorbent (GMA) for 12 wk. The major contaminant was deoxynivalenol (12.6 mg/kg of feed), with lesser amounts of zearalenone and 15-acetyl-deoxynivalenol. Feed consumption and BW were not affected by diet. The feeding of contaminated grains did not significantly affect egg production. Decreased eggshell thickness was seen, however, at the end of wk 4, and dietary supplementation with GMA prevented this effect. There was no effect of diet on other egg parameters measured. There was a significant increase in early (1 to 7 d) embryonic mortality in eggs from birds fed contaminated grains at wk 4, but mid- (8 to 14 d) and late- (15 to 21 d) embryonic mortalities were not affected by diet. There were no differences in newly hatched chick weights or viability. The ratio of chick weight to egg weight was not affected by the feeding of contaminated grains. Weight gains of chicks fed a standard broiler starter diet at 7, 14, and 21 d of age were not significantly affected by previous dietary treatments for the dam. It was found that rooster semen volume and sperm concentration, viability, and motility were not affected by the feeding of contaminated diets. There was no effect of diet on the relative weights of liver, spleen, kidney, and testes. The feeding of contaminated grains decreased antibody titers against infectious bronchitis virus at the end of wk 12, and this was prevented by dietary supplementation with GMA. There was no effect of the diet on serum antibody titers against Newcastle disease virus. It was concluded that the feeding of blends of grains contaminated with Fusarium mycotoxins could affect performance and immunity in broiler breeder hens.

Effects of feeding grains naturally contaminated with Fusarium mycotoxins with and without a polymeric glucomannan mycotoxin adsorbent on reproductive performance and serum chemistry of pregnant gilts1

Contamination of animal feedstuffs with Fusarium mycotoxins can cause reduced feed intake and hyperaminoacidemia resulting from reduced hepatic protein synthesis. The current study investigated the effects of feeding grains naturally contaminated with Fusarium mycotoxins on reproductive performance, serum chemistry, ADFI, and ADG of gilts, and tested the ability of a polymeric glucomannan mycotoxin adsorbent (GMA) to reduce or eliminate the effects of the contaminated feeds. Thirty-six Yorkshire gilts were fed 3 diets (n = 12 gilts/diet) from 91 +/- 3 d of gestation until farrowing. Diets included 1) control, 2) contaminated grains, and 3) contaminated grains + 0.2% GMA. Diets contaminated with Fusarium mycotoxins did not affect ADFI (P = 0.24), but ADG (P = 0.029) and G:F (P = 0.047) were reduced. Serum concentrations of beta-hydroxybutyrate, haptoglobin, protein, albumin, globulin, urea, glucose, cholesterol, Ca, Na, Mg, P, K, and Cl, and hepatic enzyme activities were not affected by diet. The frequency of stillborn piglets was greater (P = 0.03) for gilts fed contaminated grains compared with that of gilts fed contaminated grains + GMA. The feeding of contaminated grains + GMA also increased (P = 0.026) the percentage of pigs born alive compared with gilts fed the contaminated diets. In conclusion, feeding gilts diets that are naturally contaminated with Fusarium mycotoxins can increase the incidence of stillborn piglets and this effect can be reduced by dietary supplementation with GMA.

Effects of grazing program and subsequent finishing on gene expression in different adipose tissue depots in beef steers

This experiment was conducted to examine the effects of grazing program and subsequent finishing on gene expression in adipose tissue from steers. Twenty Angus x Angus-Hereford steer calves (initial BW = 231 +/- 25 kg) were allotted randomly to one of two winter grazing treatments: 1) grazing winter wheat pasture to achieve a high rate of BW gain (HGW); or 2) grazing dormant tallgrass native range (NR). Steers in the NR treatment were provided 0.91 kg.steer(-1).d(-1) of a 41% CP (as-fed basis) cottonseed meal supplement. Following the grazing period, steers were assigned randomly to feedlot pens. Steers were fed to a common endpoint of 1.27 cm of backfat between the 12th and 13th rib. Four steers from each treatment were slaughtered at the end of the grazing period, and the remaining steers from each treatment (n = 6) were slaughtered at the predetermined compositional endpoint. Intramuscular and s.c. fat samples were collected from LM sections of each steer at the 12th-/13th-rib interface on the left side. Pools of RNA were prepared for HGW and NR s.c. adipose tissue from steers slaughtered immediately after grazing. Suppression subtractive hybridization was performed followed by dot-blot hybridization screening to confirm differential expression of subtracted transcripts. Transcripts confirmed to be differentially expressed were subjected to dideoxy chain-termination sequencing. Quantitative reverse transcription PCR was performed on three differentially expressed clones: osteonectin, ferritin heavy chain, and decorin. Osteonectin, ferritin heavy chain, and decorin gene expression was greater (P < 0.05) in s.c. than in i.m. adipose tissue of finished steers. A depot x background interaction for osteonectin (P < 0.01) and ferritin heavy chain (P = 0.03) gene expression was observed for steers slaughtered after grazing, indicating that nutritional management can affect gene expression in adipose tissue depots differently. No differences resulting from prefinishing nutritional background (HGW or NR) were noted in osteonectin, ferritin heavy chain, or decorin gene expression in i.m. adipose tissue collected from finished steers, which might have resulted from feeding steers to the same compositional endpoint. Our data suggest that nutritional background alters gene expression in adipose depots, and that depots are influenced differently.

Effects of feed-borne Fusarium mycotoxins on hematology and immunology of turkeys

Feeding grains naturally-contaminated with Fusarium mycotoxins has been shown to alter the metabolism and performance of turkeys. The objectives of the current experiment were to examine the effects of feeding turkeys with grains naturally contaminated with Fusarium mycotoxins on their hematology and immunological indices (including functions), and the possible protective effect of feeding a polymeric glucomannan mycotoxin adsorbent (GMA). Two hundred twenty-five 1-d-old male turkey poults were fed corn, wheat, and soybean meal-based starter (0 to 3 wk), grower (4 to 6 wk), developer (7 to 9 wk), and finisher (10 to 12 wk) diets formulated with uncontaminated grains, contaminated grains, or contaminated grains with 0.2% GMA. The chronic consumption of Fusarium mycotoxins caused minor and transient changes in hematocrit (0.33 L/L) and hemoglobin (10(6) g/L) concentrations as well as in blood basophil (0.13 x 10(9)/L) and monocyte counts (3.42 x 10(9)/L) compared with controls. Supplementation of the contaminated diet with GMA prevented these effects on blood cell counts. Biliary IgA concentrations were significantly increased (4.45-fold) when birds were fed contaminated grains compared with controls, but serum IgA concentrations were not affected. Contact hypersensitivity to dinitrochlorobenzene, which is a CD8+ T-cell-mediated delayed-type hypersensitivity response, was decreased (48%) by feed-borne mycotoxins compared with the control. By contrast, the primary and secondary antibody response to sheep red blood cells, a CD4+ T-cell-mediated response, was not affected. It was concluded that chronic consumption of grains naturally contaminated with Fusarium mycotoxins exerts only minor adverse effects on the hematology and some immunological indices of turkeys. Consumption of grains naturally contaminated with Fusarium mycotoxins may, however, increase the susceptibility of turkeys to infectious agents against which CD8+ T cells play a major role in defense.

Effects of feed-borne Fusarium mycotoxins on hematology and immunology of laying hens

Feeding grains naturally contaminated with Fusarium mycotoxins has been shown to alter metabolism and performance of laying hens. The objectives of the current experiment were to examine the effects of feeding grains naturally contaminated with Fusarium mycotoxins on hematology and immunological indices and functions of laying hens and the possible protective effect of feeding a polymeric glucomannan mycotoxin adsorbent (GMA). One hundred forty-four laying hens were fed for 12 wk with diets formulated with (1) uncontaminated grains, (2) contaminated grains, or (3) contaminated grains + 0.2% GMA. Fusarium mycotoxins such as deoxynivalenol (DON, 12 mg/kg), 15-acetyl-DON (0.5 mg/kg), and zearalenone (0.6 mg/kg) were identified in the contaminated diets arising from contaminated grains grown in Ontario, Canada. The concentrations of DON arising from naturally contaminated grains in this study were similar to purified mycotoxin fed to experimental mice. The chronic feeding of Fusarium mycotoxins induced small decreases in hematocrit values, total numbers of white blood cells, lymphocytes including both CD4+ and CD8+ T lymphocytes and B lymphocytes, and biliary IgA concentration. Supplementation of diets containing feedborne mycotoxins with GMA prevented the reduction in total number of B lymphocytes in the peripheral blood and the reduction in biliary IgA concentration. In addition, the delayed-type hypersensitivity response to dinitrochlorobenzene was increased by feed-borne mycotoxins, whereas IgG and IgM antibody titers to sheep red blood cells were not affected by diet. We concluded that chronic consumption of grains naturally contaminated with Fusarium mycotoxins at levels likely to be encountered in practice were not systemically immunosuppressive or hematotoxic; however, mucosal immunocompetence needs to be explored further.

GABA-induced calcium signaling in cultured enteric neurons is reinforced by activation of cholinergic pathways

GABA is an important inhibitory transmitter in the CNS. In the enteric nervous system, however, both excitatory and inhibitory actions have been reported. Here, we investigated the effects of GABA on the intracellular Ca2+ concentration of guinea-pig myenteric neurons (at 35 degrees C) using Fura-2-AM. Neurons were identified by 75 mM K+ depolarization (5 s), which evoked a transient intracellular Ca2+ concentration increase. GABA (10 s) induced a dose dependent (5 nM-1 microM) transient intracellular Ca2+ concentration rise in the majority of neurons (500 nM GABA: 251+/-17 nM, n=232/289). Interestingly, the response to 5 microM GABA (n=18) lasted several minutes and did not fully recover. GABA response amplitudes were significantly (P<0.001) reduced by GABAA and GABAB receptor antagonists (10 microM) bicuculline and phaclofen. The GABAA agonist isoguvacine (10 microM) and GABAB agonist baclofen (10 microM) induced similar responses as 50 nM GABA, while the GABAC agonist cis-4-aminocrotonic acid (CACA) (10 microM) only elicited small responses in a minority of neurons. Removal of extracellular Ca2+ abolished all responses while depletion of intracellular Ca2+ stores by thapsigargin (5 microM) did not alter the responses to 500 nM GABA (n=13), but reduction of Ca2+ influx through voltage-dependent Ca2+ channels did. The nicotinic antagonist hexamethonium (100 microM) also reduced GABA responses by almost 70% suggesting that GABA stimulates cholinergic pathways, while the purinergic receptor blocker pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS) and the 5-HT3 receptor blocker ondansetron only had minor effects.

CONCLUSION

GABA elicits transient intracellular Ca2+ concentration responses in the majority of myenteric neurons through activation of GABAA and GABAB receptors and much of the response can be attributed to facilitation of ACh release. Thus GABA may act mainly as a modulator that sets the state of excitability of the enteric nerve network. A concentration of 5 microM GABA, although frequently used in pharmacological experiments, seems to cause a detrimental response reminiscent of the neurotoxic effects glutamate has in the CNS.

Effects of feeding grains naturally contaminated with Fusarium mycotoxins on hepatic fractional protein synthesis rates of laying hens and the efficacy of a polymeric glucomannan mycotoxin adsorbent

Experiments were conducted to evaluate the effects of feeding grains naturally contaminated with a combination of Fusarium mycotoxins on hepatic fractional protein synthesis rates (FSR) of laying hens. Thirty-six 32-wk-old laying hens were fed diets formulated with 1) uncontaminated grains, 2) contaminated grains, or 3) contaminated grains + 0.2% polymeric glucomannan mycotoxin adsorbent for a period of 4 wk. Hepatic FSR were measured in vivo by the flooding-dose method. The feeding of contaminated grains decreased hepatic FSR in laying hens compared with controls after 4 wk. The hepatic FSR of birds fed contaminated grains and contaminated grains + glucomannan mycotoxin adsorbent were not different. It was concluded that the in vivo hepatic FSR of laying hens was inhibited by the feeding of grains naturally contaminated with Fusarium mycotoxins and that this may explain some of the adverse effects seen when contaminated grains were fed to laying hens.

The myo-inositol-1-phosphate synthase gene is essential in Trypanosoma brucei

The de novo synthesis of myo-inositol occurs via a two-step process: first, glucose 6-phosphate is converted into inositol 1-phosphate by an INO1 (myo-inositol-1-phosphate synthase; EC 5.5.1.4); then, it is dephosphorylated by an inositol monophosphatase. The myo-inositol can then be incorporated into PI (phosphatidylinositol), which is utilized in a variety of cellular functions, including the biosynthesis of GPI (glycosylphosphatidylinositol) anchors. A putative INO1 was identified in the Trypanosoma brucei genome database and, by recombinant expression in Escherichia coli, was shown to be a catalytically active INO1. To investigate the importance of INO1, we created a conditional knockout, which, under non-permissive conditions, showed that INO1 is an essential gene in bloodstream form T. brucei and that the de novo synthesized myo-inositol is used for the formation of PI and GPI anchors.

Effects of feeding blends of grains naturally contaminated with Fusarium mycotoxins on performance, metabolism, hematology, and immunocompetence of ducklings

Experiments were conducted to determine the effects of feeding grains naturally contaminated with Fusarium mycotoxins on performance, metabolism, hematology, and immune competence of ducklings. Four hundred sixty-four 1-d-old White Pekin male ducklings were fed starter (0 to 2 wk), grower (3 to 4 wk), and finisher (5 to 6 wk) diets formulated with uncontaminated grains, a low level of contaminated grains, a high level of contaminated grains, or the higher level of contaminated grains + 0.2% polymeric glucomannan mycotoxin adsorbent. Body weight gains, feed consumption, and feed efficiency were not affected by diet. However, consumption of contaminated grains decreased plasma calcium concentrations after 2 wk and plasma uric acid concentrations at the 4-wk assessment point. Mean corpuscular hemoglobin concentrations and hematocrit decreased when ducks were fed contaminated grains for 4 or 6 wk, respectively. In contrast, total numbers of white blood cells and lymphocytes increased transiently in birds fed contaminated grains for 4 wk. The antibody response to sheep red blood cells (CD4+ T cell dependent) and the cell-mediated response to phytohemagglutinin-P (also CD4+ T cell dependent) were not affected by diet, but consumption of contaminated grains for 6 wk decreased the duration of peak cell-mediated response to dinitrochlorobenzene (CD8+ T cell dependent) assessed in a skin test. Feeding grains naturally contaminated with Fusarium mycotoxins, even at levels widely regarded as high, exerted only minor adverse effects on plasma chemistry and hematology of ducklings, and production parameters were unaffected in this avian species. Mycotoxin-contaminated feeds may, however, render these animals susceptible to infectious agents such as viruses against which the CD8+ T cell provides necessary defence. Glucomannan mycotoxin adsorbent was not effective in preventing alterations caused by Fusarium mycotoxins.

Thyroid status and nitric oxide in rat arterial vessels

Thyroid disease has profound effects on cardiovascular function. Hypo- and hyperthyroidism, for example, are associated with reduced and increased maximal endothelium-dependent vasodilation respectively. We therefore hypothesized that the capacity for vascular nitric oxide (NO) formation is decreased in hypothyroidism and increased in hyperthyroidism. To test this hypothesis, rats were made hypothyroid (HYPO) with propylthiouracil or hyperthyroid (HYPER) with triiodothyronine over 3-4 months. Compared with euthyroid control rats (EUT), HYPO exhibited blunted growth and lower citrate synthase activity in the soleus muscle; HYPER exhibited left ventricular hypertrophy and higher citrate synthase activity in the soleus muscle (P<0.05 for all effects). The capacity for NO formation was determined in aortic extracts by formation of [3H]L-citrulline from [3H]L-arginine, i.e. NO synthase (NOS) activity. Thyroid status modulated NOS activity (EUT, 36.8 +/- 5.5 fmol/h per mg protein; HYPO, 26.0 +/- 7.9; HYPER, 64.6 +/- 12.7; P<0.05, HYPER vs HYPO). Expression of endothelial and neural isoforms of NOS was modulated by thyroid status in a parallel fashion. Capacity for responding to NO was also determined via measuring cGMP concentration in aortae incubated with sodium nitroprusside. Stimulated cGMP formation was also modulated by thyroid status (EUT, 73.0 +/- 20.2 pmol/mg protein; HYPO, 152.4 +/- 48.7; HYPER, 10.4 +/- 2.6; P<0.05, HYPER vs HYPO). These data indicate that thyroid status alters capacities for both formation of and responding to NO. The former finding may contribute to previous findings concerning vascular function in thyroid disease states.

Effects of dietary tamarind on cholesterol metabolism in laying hens

An experiment was conducted to evaluate the potential for dietary tamarind to alter serum and egg yolk cholesterol concentrations and overall performance in different layer strains. Thirty, 43-wk-old, Hisex Brown, ISA Brown, Lohmann Brown, Starcross Brown, Babcock B-300, and Starcross-579 strains (5 hens per strain) were fed diets supplemented with 0 (control), 2, 4, 6, or 8% oven-dried tamarind for 6 wk. Egg production, egg mass, and efficiency of feed utilization followed a quadratic response with a maximum when the diet contained 2% tamarind and a minimum when 8% tamarind was fed (P < 0.05). There were no differences (P > 0.05) among strains for egg production, egg weight, yolk weight, egg mass, feed consumption, or feed efficiency. Yolk weight increased linearly (P < 0.05) with increasing levels of dietary tamarind in wk 1, 2, and 3 as well as when averaged over 6 wk. Egg yolk cholesterol concentrations were not affected by dietary tamarind. Serum cholesterol concentrations, however, decreased quadratically with increasing levels of dietary tamarind (P < 0.05). It was concluded that 2% supplemental dietary tamarind could decrease serum cholesterol concentrations and increase layer performance.

Effects of feeding blends of grains naturally contaminated with Fusarium mycotoxins on performance and metabolism of laying hens

An experiment was conducted to evaluate the effects of feeding laying hens grains naturally contaminated with a combination of Fusarium mycotoxins. Parameters measured included performance, organ weights, and plasma chemistry. One hundred and forty-four, 45-wk-old laying hens were fed diets including: (1) control, (2) contaminated grains, and (3) contaminated grains + 0.2% polymeric glucomannan mycotoxin adsorbent (GMA) for a 12-wk period. The feeding of contaminated grains decreased feed consumption compared with controls in the first 4 wk. Feed consumption increased, however, from 4 to 8 wk and from 8 to 12 wk. The efficiency of feed utilization (feed consumption/egg mass) decreased compared with controls in the periods from 4 to 8 and from 8 to 12 wk when birds were fed contaminated grains. Supplementation with GMA decreased feed consumption and increased the efficiency of feed utilization in the period from 8 to 12 wk. Egg production and egg mass decreased in wk 4 and 8 compared with controls when contaminated grains were fed, whereas egg and eggshell weights decreased in the fourth wk. Plasma uric acid concentrations increased throughout the experiment and relative kidney weights increased at the end of the experiment compared with controls when birds were fed contaminated grains. The feeding of GMA prevented the elevation in uric acid concentrations and relative kidney weights. It was concluded that layer performance and metabolism were adversely affected by chronic feeding of a combination of Fusarium mycotoxins, and that GMA prevented many of these effects.

Effects of feeding blends of grains naturally contaminated with Fusarium mycotoxins on brain regional neurochemistry of starter pigs and broiler chickens1

Two experiments were conducted to compare the effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins on brain regional neurochemistry of starter pigs and broiler chickens. A polymeric glucomannan mycotoxin adsorbent (GM polymer) was also tested for its efficacy in preventing Fusarium mycotoxicoses. In Exp. 1, a total of 150 starter pigs (initial weight = 9.3+/-1.1 kg) were fed five diets (six pens of five pigs per diet) for 21 d. Diets (as-fed basis) included control, 17% contaminated grains, 24.5% contaminated grains, 24.5% contaminated grains + 0.2% GM polymer, and a pair-fed control for comparison with pigs receiving 24.5% contaminated grains. In Exp. 2,360 1-d-old male broiler chicks were fed for 56 d one of four diets containing the same source of contaminated grains as was fed to pigs. The diets included control, 37% contaminated grains, 58% contaminated grains, and 58% contaminated grains + 0.2% GM polymer (as fed). Neurotransmitter concentrations in the cortex, hypothalamus, and pons were analyzed by HPLC. The following brain neurotransmitter alterations (P < or = 0.05) were observed. In pigs, inclusion of contaminated grains in the diet 1) linearly increased cortex 5-hydroxytryptamine (5HT, serotonin) concentrations, while linearly decreasing hypothalamic tryptophan concentrations; 2) quadratically increased hypothalamic and pons 5-hydroxyindoleacetic acid (5HIAA):5HT ratios, whereas the ratio decreased linearly in the cortex; and 3) linearly increased the ratio of hypothalamic 3,4-dihydroxyphenylacetic acid:dopamine (DA) concentrations, whereas hypothalamic norepinephrine (NRE) and pons DA and homovanillic acid (HVA) concentrations linearly decreased. In broiler chickens, inclusion of contaminated grains in the diet 1) linearly increased concentrations of 5HT and 5HIAA in the pons and 5HT concentrations in the cortex; 2) linearly decreased 5HIAA:5HT ratio; and 3) linearly increased pons NRE, 3-methoxy-4-hydroxyphenylethylene glycol, DA, and HVA concentrations. Supplementation of GM polymer to the contaminated diet decreased (P < 0.05) 5HT and 5HIAA concentrations in the cortex of pigs. It was concluded that the differences in alterations of brain neurochemistry might explain the species differences in the severity of Fusarium mycotoxin-induced feed refusal.

Calcium imaging of gut activity

The major cell types regulating gut motility include enteric neurones, interstitial cells of Cajal (ICC) and their effector smooth muscle cells. These cells are arranged conveniently in nested layers through the gut wall. Our knowledge of how many of these cells in each layer are integrated to produce the various patterns of motility is largely unknown. So far, much of our knowledge of gut motility has usually been obtained by examining point sources of activity (e.g. intracellular recordings from enteric neurones, ICC and smooth muscle cells), rather than the spread of activity through these spatially distributed nerve and ICC networks, or smooth muscle syncitia. Our understanding of how these cells are integrated to produce gut movements would be greatly enhanced if we could image the activity in many of these cells in each layer, or many cells in several layers, simultaneously. Calcium (Ca2+) is a major signalling and regulatory molecule in most cells. In fact, electrical excitability in enteric neurones, ICC and smooth muscle is associated with robust rises in intracellular Ca2+ that long outlast the electrical events (e.g. action potentials in neurones and smooth muscle) that gave rise to them. These prolonged Ca2+ responses, together with the development of several high quality Ca2+ indicators, has provided a unique opportunity to image many cells in intact tissues simultaneously using ICCD video-rate cameras along with conventional microscopy. However, confocal microscopy has also been used, and has several advantages over the above systems. These include reduced photo-toxicity and bleaching and the elimination of out of focus light from different layers within the tissue. So far, despite some limitations with the calcium imaging techniques, the spread of activity through the two layers of smooth muscle, ICC networks and myenteric neurones in intact preparations, or cultured myenteric neuronal networks, is beginning to yield exciting new data about how these different cells interact and process information.

Effects of feeding blends of grains naturally contaminated with Fusarium mycotoxins on growth and immunological parameters of broiler chickens

An experiment was conducted to investigate the effects of feeding grains naturally contaminated with Fusarium mycotoxins on growth and immunological parameters of broiler chickens. Three hundred sixty, 1-d-old male broiler chicks were fed 1 of 4 diets containing grains naturally contaminated with Fusarium mycotoxins for 56 d. The diets included (1) control; (2) low level of contaminated grains (5.9 mg/kg deoxynivalenol (DON), 19.1 mg/kg fusaric acid (FA), 0.4 mg/kg zearalenone, and 0.3 mg/kg 15-acetyldeoxynivalenol; (3) high level of contaminated grains (9.5 mg/kg DON, 21.4 mg/kg FA, 0.7 mg/kg zearalenone, and 0.5 mg/kg 15-acetyldeoxynivalenol); and (4) high level of contaminated grains + 0.2% polymeric glucomannan mycotoxin adsorbent (GM polymer). Body weight gains and feed consumption of chickens fed contaminated grains decreased linearly with the inclusion of contaminated grains during the grower phase (d 21 to 42). Efficiency of feed utilization, however, was not affected by diet. Production parameters were not significantly affected by the supplementation of GM polymer to the contaminated grains. Peripheral blood monocytes decreased linearly in birds fed contaminated grains. The feeding of contaminated diets linearly reduced the B-cell count at the end of the experiment, whereas the T-cell count on d 28 responded quadratically to the contaminated diets. The feeding of contaminated diets did not significantly alter serum or bile immunoglobulin concentrations, contact hypersensitivity to dinitrochlorobenzene, or antibody response to SRBC. Supplementation with GM polymer in the contaminated diet nonspecifically increased white blood cell count and lymphocyte count, while preventing mycotoxin-induced decreases in B-cell counts. It was concluded that broiler chickens are susceptible during extended feeding of grains naturally contaminated with Fusarium mycotoxins.

Propagation of pacemaker activity in the guinea-pig antrum

Cyclical periods of depolarization (slow waves) underlie peristaltic contractions involved in mixing and emptying of contents in the gastric antrum. Slow waves originate from a myenteric network of interstitial cells of Cajal (ICC-MY). In this study we have visualized the sequence and propagation of Ca(2+) transients associated with pacemaker potentials in the ICC network and longitudinal (LM) and circular muscle (CM) layers of the isolated guinea-pig gastric antrum. Gastric antrum was dissected to reveal the ICC-MY network, loaded with Fluo-4 AM and activity was monitored at 37 degrees C. Ca(2+) waves propagated throughout the ICC-MY network at an average velocity of 3.24 +/- 0.12 mm s(-1) at a frequency of 4.87 +/- 0.16 cycles min(-1) (n= 4). The propagation of the Ca(2+) wave often appeared 'step-like', with separate regions of the network being activated after variable delays. The direction of propagation was highly variable (Delta angle of propagation 44.3 +/- 10.9 deg per cycle) and was not confined to the axes of the longitudinal or circular muscle. Ca(2+) waves appeared to spread out radially from the site of initiation. The initiating Ca(2+) wave in ICC-MY was correlated to secondary Ca(2+) waves in intramuscular interstitial cells of Cajal, ICC-IM, and smooth muscle cells, and the local distortion (contraction) in a field of view. TTX (1 microm) had little effect on slow wave or pacemaker potential activity, but 2-APB (50 microm) blocked all Ca(2+) waves, indicating a pivotal role for intracellular Ca(2+) stores. Nicardipine (2 microm) eliminated the Ca(2+) transient generated by smooth muscle, but did not affect the fast upstroke associated with ICC-MY. These results indicate that slow waves follow a sequence of activation, beginning with the ICC-MY and ICC-IM network, followed later by a sustained Ca(2+) transient in the muscle layers that is responsible for contraction.

Effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins on growth and immunological measurements of starter pigs, and the efficacy of a polymeric glucomannan mycotoxin adsorbent1

An experiment was conducted to investigate the effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins on growth and immunological parameters of starter pigs. A polymeric glucomannan mycotoxin adsorbent (GM polymer, Alltech Inc., Nicholasville, KY) was also tested for its efficacy in preventing Fusarium mycotoxicoses. A total of 150 starter pigs (initial weight of 9.3 +/- 1.1 kg) were fed one of five treatment diets (six pens of five pigs per diet) for 21 d. Diets included control, low level of contaminated grains, high level of contaminated grains, high level of contaminated grains + 0.20% GM polymer, and pair-fed control for comparison with pigs receiving the high level of contaminated grains. Feed intake and cumulative weight gain of pigs decreased linearly with the inclusion of contaminated grains in the diet throughout the experiment (P < 0.0001). Weight gains recovered, however, during wk 3 (P > 0.05). There was no difference between the pair-fed group and the pigs fed the diet containing the high level of contaminated grains in terms of weight gain or feed efficiency (P > 0.05). Feeding contaminated grains linearly increased the serum albumin:globulin ratio (P = 0.01), whereas serum urea concentrations and gamma-glutamyltransferase activities responded in a quadratic fashion (P = 0.02). When compared with the pair-fed pigs, serum concentrations of total protein (P = 0.01) and globulin (P = 0.02) were decreased in pigs fed the diet containing the high level of contaminated grains. The feeding of contaminated diets did not significantly alter organ weights expressed as a percentage of BW, serum immunoglobulin concentrations, percentages of peripheral blood lymphocyte subsets, contact hypersensitivity to dinitrochlorobenzene, or primary antibody response to sheep red blood cells (P > 0.05). It was concluded that most of the adverse effects of feeding Fusarium mycotoxin-contaminated grains to starter pigs were caused by reduced feed intake. Although supplementation of GM polymer to the contaminated diet prevented some toxin-induced changes in metabolism, it did not prevent the mycotoxin-induced growth depression under the current experimental conditions.

Effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins on feed intake, serum chemistry, and hematology of horses, and the efficacy of a polymeric glucomannan mycotoxin adsorbent

The feeding of Fusarium mycotoxin-contaminated grains adversely affects the performance of swine and poultry. Very little information is available, however, on adverse effects associated with feeding these mycotoxin-contaminated grains on the performance of horses. An experiment was conducted to investigate the effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins on feed intake, serum immunoglobulin (Ig) concentrations, serum chemistry, and hematology of horses. A polymeric glucomannan mycotoxin adsorbent (GM polymer) was also tested for efficacy in preventing Fusarium mycotoxicoses. Nine mature, nonexercising, light, mixed-breed mares were assigned randomly to one of three dietary treatments for 21 d. The horses were randomly reassigned and the experiment was subsequently replicated in time following a 14-d washout interval. Feed consumed each day was a combination of up to 2.8 kg of concentrates and 5 kg of mixed timothy/alfalfa hay. The concentrates fed included the following: 1) control, 2) blend of contaminated grains (36% contaminated wheat and 53% contaminated corn), and 3) blend of contaminated grains + 0.2% GM polymer. Diets containing contaminated grains averaged 15.0 ppm of deoxynivalenol, 0.8 ppm of 15-acetyldeoxynivalenol, 9.7 ppm of fusaric acid, and 2.0 ppm of zearalenone. Feed intake by all horses fed contaminated grains was reduced (P < 0.001) compared with controls throughout the experiment. Supplementation of 0.2% GM polymer to the contaminated diet increased (P = 0.004) feed intake of horses compared with those fed the unsupplemented contaminated diet. Serum activities of gamma-glutamyltransferase were higher (P = 0.047 and 0.027) in horses fed the diet containing contaminated grain compared with those fed the control diet on d 7 and 14, but not on d 21 (P = 0.273). Supplementation of GM polymer to the contaminated diet decreased (P < 0.05) serum gamma-glutamyltransferase activities of horses compared with those fed unsupplemented contaminated diet on d 7 and 14. Other hematology and serum chemistry measurements including serum IgM, IgG, and IgA, were not affected by diet. It was concluded that the feeding of grains naturally contaminated with Fusarium mycotoxins caused a decrease in feed intake and altered serum gamma glutamyltransferase activities. The supplementation of GM polymer prevented these mycotoxin-induced adverse effects.

Effects of dietary garlic on cholesterol metabolism in laying hens

Experiments were conducted to evaluate the potential for dietary garlic to influence egg yolk cholesterol concentrations and overall performance in different layer strains. Thirty-six, 28-wk-old, Hisex Brown,Isa Brown, Lohmann, Starcross, Babcock, and Starcross-579 strains (six hens per strain) were fed diets supplemented with 0 (control), 2, 4, 6, 8, or 10% sun-dried garlic paste for 6 wk. There were no differences (P > 0.05) among diets or strains in egg weight, egg mass, feed consumption, feed efficiency, and BW gain as averaged over 6 wk. Yolk weight, however, responded quadratically with increasing levels of dietary garlic and differed among strains (P < 0.05). Egg production and yolk weights were significantly higher in the Babcock strain in comparison with other strains. Serum and egg yolk cholesterol concentrations decreased linearly (P < 0.05) with increasing levels of dietary garlic. Serum and egg yolk cholesterol concentrations also differed among different strains (P < 0.05). It was concluded that garlic paste in the diets of laying hens reduced serum and yolk cholesterol concentrations. It was also concluded that dietary garlic paste had no adverse effects on layer performance.

Effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins on swine performance, brain regional neurochemistry, and serum chemistry and the efficacy of a polymeric glucomannan mycotoxin adsorbent

The co-occurrence of Fusarium mycotoxins in contaminated swine diets has been shown to result in synergistic toxicity beyond that observed for individual toxins. An experiment was conducted, therefore, to investigate the effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins on growth, brain regional neurochemistry, serum immunoglobulin (Ig) concentrations, serum chemistry, hematology, and organ weights of starter pigs. Three levels of glucomannan polymer (GM polymer, extract of yeast cell wall, Alltech Inc.) were also tested for its efficacy to overcome Fusarium mycotoxicoses. A total of 175 starter pigs (initial weight of 10 +/- 1.1 kg) were fed five diets (seven pens of five pigs per diet) for 21 d. Diets included (1) control, (2) blend of contaminated grains, (3) contaminated grains + 0.05% GM polymer (4) contaminated grains + 0.10% GM polymer and (5) contaminated grains + 0.20% GM polymer. Diets containing contaminated grains averaged 5.5 ppm deoxynivalenol, 0.5 ppm 15-acetyldeoxynivalenol, 26.8 ppm fuuric acid, and 0.4 ppm zearalenone. Feed intake and weight gain of all pigs fed contaminated grains was significantly reduced compared to controls throughout the experiment. The weights of liver and kidney, expressed as a percentage of body weight, were lower in pigs fed the contaminated diet than in those fed the control diet. The feeding of contaminated grains significantly reduced concentrations of dopamine in the hypothalamus and pons and concentrations of dihydroxyphenylacetic acid and norepinephrine in the pons. The ratios of 5-hydroxyindoleacetic acid to serotonin, however, were elevated in the hypothalamus and pons. The feeding of contaminated grains increased serum IgM and IgA concentrations, while serum IgG concentrations were not altered. The supplementation of GM polymer prevented some of the mycotoxin-induced alterations in brain neurotransmitter and serum Ig concentrations. In summary, the feeding of grains naturally contaminated with Fusarium mycotoxins reduced growth, altered brain neurochemistry, increased serum Ig concentrations, and decreased organ weights in starter pigs. Some of the Fusarium mycotoxin-induced changes in neurochemistry and serum Ig concentrations can be prevented by the feeding of yeast cell wall polymer at appropriate concentrations, although this was not reflected in increased growth rate under these experimental conditions.

Effects of feeding blends of grains naturally contaminated with Fusarium mycotoxins on production and metabolism in broilers

Three hundred sixty, 1-d-old male broiler chicks were fed diets containing grains naturally contaminated with Fusarium mycotoxins for 56 d. The four diets included control (0.14 mg/kg deoxynivalenol, 18 mg/ kg fusaric acid, < 0.1 mg/kg zearalenone), low level of contaminated grains (4.7 mg/kg deoxynivalenol, 20.6 mg/kg fusaric acid, 0.2 mg/kg zearalenone), and high level of contaminated grains without (8.2 mg/kg deoxynivalenol, 20.3 mg/kg fusaric acid, 0.56 mg/kg zearalenone) and with (9.7 mg/kg deoxynivalenol, 21.6 mg/kg fusaric acid, 0.8 mg/kg zearalenone) 0.2% esterified-glucomannan polymer derived from Saccharomyces cerevisiae1026 (E-GM). Body weight gain and feed consumption responded in a significant quadratic fashion to the inclusion of contaminated grains during the finisher period. Efficiency of feed utilization, however, was not affected by diets. The feeding of contaminated grains in the finisher period also caused significant linear increases in blood erythrocyte count and serum uric acid concentration and a significant linear decline in the serum lipase activity. Dietary inclusion of contaminated grains resulted in a significant quadratic effect on serum albumin and y-glutamyltransferase activity. Blood hemoglobin and biliary IgA concentrations, however, responded in significant linear and quadratic fashions. Supplementation of E-GM counteracted most of the blood parameter alterations caused by the Fusarium mycotoxin-contaminated grains and reduced breast muscle redness. It was concluded that broiler chickens may be susceptible to Fusarium mycotoxicoses when naturally contaminated grains are fed containing a combination of mycotoxins.

Dietary interaction of 1,4-diaminobutane (putrescine) and calcium on eggshell quality and performance in laying hens

An experiment was conducted to evaluate the potential dietary interaction between 1,4-diaminobutane (putrescine) and calcium on eggshell quality and overall laying performance. One hundred ninety-two 30-wk-old White Leghorn hens were fed a corn-and soybean-meal-based diet supplemented with 0.00, 0.05, 0.10, or 0.15% putrescine and 2.5, 3.0, 3.5, or 4.0% calcium in a factorial design (12 birds per diet) for 4 wk. The percentage of egg production increased linearly (P < 0.05) with increasing levels of dietary calcium. Significant interactions (P < 0.05) were observed between dietary putrescine and calcium for eggshell thickness, eggshell deformation, percentage of eggshell, calcium intake, total calcium retention, total eggshell calcium, and percentage of eggshell calcium. Interactions were due to quadratic effects of putrescine or calcium on these parameters. Eggshell thickness and percent eggshell increased when hens were fed 3.5% calcium in combination with 0.1% putrescine; however, calcium intake and calcium retention were significantly lower (P < 0.05). Eggshell quality improved with increasing dietary levels of calcium due to increased calcium retention and calcium balance. Increasing levels of dietary putrescine did not have a negative effect on eggshell quality; however, calcium intake was lower at higher-supplemented levels of putrescine. It was observed that dietary calcium in excess of requirements resulted in increased egg production and eggshell quality. Eggshell quality improved when hens were fed 3.5% calcium diet in combination with 0.10% putrescine. It was concluded that small supplements of dietary putrescine may improve eggshell quality, depending on dietary calcium concentration.