Comparison of a novel form of zinc with zinc oxide bolus licensed for prevention of facial eczema, and interaction with copper oxide in sheep.

To evaluate a novel elemental zinc bolus compared with a registered positive control zinc oxide bolus and assess serum zinc concentrations following concomitant treatment with a capsule containing copper oxide needles. Forty Romney-cross ewes were randomly allocated in a 2 × 2 factorial design study. On Day 0, 20 ewes received novel boluses containing elemental zinc (Investigational Veterinary Product, IVP) while 20 received a zinc oxide bolus (control; CP). Half the animals in each zinc treatment group (n = 10) were treated with a copper oxide needle capsule [Copasure® - Ewe]. Weekly, from Day -7 to 56, all ewes were assessed for signs of photosensitization, and for 10 ewes from each zinc treatment groups, samples were collected for analysis of serum GGT activity, serum zinc concentrations, faecal zinc concentrations and on Days -7 and 56, liver copper concentrations. Multivariable random-effects models assessed the effects of zinc treatment, copper treatment, treatment interactions and time on all analytes. Regression models examined associations between serum and faecal zinc concentrations and GGT activity. Low spore numbers indicated low Pithomyces chartarum challenge. Serum zinc levels were significantly higher in the IVP than in the CP group [p < 0.0001] and varied by time [p < 0.001] and positively associated with faecal zinc concentration [p < 0.001]. Copper treatment did not affect serum zinc [p = 0.82] or faecal zinc [p = 0.92] concentrations. Liver copper concentrations did not differ between zinc treatment groups on Day -7 [p = 0.6] or Day 56 [p = 0.95]. Only the CP/no copper group had no increase in liver copper concentrations.

Aflatoxins in Feed: Types, Metabolism, Health Consequences in Swine and Mitigation Strategies.

Feeding farm animals with aflatoxin-contaminated feed can cause various severe toxic effects, leading to increased susceptibility to infectious diseases and increased mortality, weight loss, poor performance and reduced reproductive capability. Following ingestion of contaminated foodstuffs, aflatoxins are metabolized and biotransformed differently in animals. Swine metabolism is not effective in detoxifying and excreting aflatoxins, meaning the risk of aflatoxicosis is increased. Thus, it is of great importance to elucidate the metabolism and all metabolic pathways associated with this mycotoxin. The damage induced by AFB1 in cells and tissues consists of inhibition of cell proliferation, carcinogenicity, immunosuppression, mutagenicity, oxidative stress, lipid peroxidation and DNA damage, leading to pathological lesions in the liver, spleen, lymph node, kidney, uterus, heart, and lungs of swine. At present, it is a challenging task and of serious concern to completely remove aflatoxins and their metabolites from feedstuff; thus, the aim of this study was a literature review on the deleterious effects of aflatoxins on swine metabolism, as well as alternatives that contribute to the detoxification or amelioration of aflatoxin-induced effects in farm animal feed.

Acute aflatoxicosis outbreak in rheas (Rhea americana) in Brazil: Case report.

Aflatoxins are mycotoxins capable of contaminating food, and can cause toxic effects, teratogenicity, mutagenicity, carcinogenicity, and immune system depression. The presence of fungi which produce this metabolite in ingredients that compose the animal feed increased the risk of the emergence of aflatoxicosis. The objective of this study was to report an aflatoxicosis outbreak in rheas (Rhea americana) from a farm in Teresina, PI, Brazil, fed with commercial feed. After the deaths of four animals, epidemiological data were collected and complementary examinations were performed, including necropsy, histopathology, parasitology, blood culture, in addition to the analysis of the presence of toxins in the birds' feed. The diagnosis was based on the acute clinical signs, necropsy findings, which included carcass jaundice, an oedematous, yellowish, friable liver of increased size, and histopathological findings of moderate to severe congestion in all organs. The parasitological and microbiological tests performed were negative, not indicating systemic infectious causes. The analysis of the presence of mycotoxins revealed the existence of Aflatoxins B1, B2 and G1 in the commercial feed supplied, constituting a total of 66.89 µg/kg. This amount of aflatoxin exceeds the maximum level allowed by the Brazilian legislation. To our knowledge this is the first report of aflatoxicosis in rheas, and emphasizes the importance of the diagnosis, control, and prevention of mycotoxins in the quality of food provided to animals kept ex situ.

Clinical and pathological examination of mycotoxicosis as an associated risk factor for colic in equine.

A retrospective cohort study was conducted on two Egyptian horse farms with most of horses were suffered from abdominal pain to describe the associations between the occurrence of mycotoxicosis and equine colic. The farms owner complain was an unexpected increase in number of colic cases and deaths among horses. The association between colic and risk factors (sex, type of food either dry or mixed with roughages and hematobiochemical parameters) was compared using independent sample T-test. The associations between possible prognostic indicators for colic caused by mycotoxicosis was estimated using logistic regression analysis model. The cumulative incidence, incidence rates for colic attacks, survival rate among diseased horses were additionally estimated. Our results showed that a total of 24 out of the 132 horses suffered from colic due to feeding of ration contaminated with high percent of mycotoxin including Aflatoxins, Ochratoxins and or fusarium mycotoxins. The total cumulative incidence of colic due to mycotoxicosis was 19.7%. The horses fed on dry rations had more chance of developing colic than horses fed on mixed rations (P < 0.05). The overall incidence rate of colic due to mycotoxicosis was estimated at 18 colic attack/1000 horse/month. The mortality rate of horses suffered from colic due to mycotoxicosis was estimated at 5.9% (5/85), while the case fatality rate was estimated at 25% (n = 5/20). Inconclusion, our results showed that mycotoxicosis are considered an important risks factor for colic cases development in equine practice.

The ameliorative effects of Nigella sativa, thymoquinone, and bentonite against aflatoxicosis in broilers via AFAR and Nrf2 signalling pathways, and down-regulation of caspase-3.

1. Aflatoxins (AFs) are metabolites which especially have toxic effects on proteins, and are detoxified by the aflatoxin-B1 aldehyde reductase (AFAR) pathway. In this pathway, the aldo-keto reductase family 7, member A2 (AKR7A2) enzyme, which is controlled by nucleic-related erythroid factor 2 (Nrf2), plays an active role. However, data on the efficacy of this critical pathway in broilers is limited.2. The aim of the following study was to investigate the changes in the expression levels of AKR7A2, Nrf2, and caspase-3, and the effects of Nigella sativa seeds (NS), thymoquinone (TMQ), and bentonite (BNT) in broilers exposed to AFs.3. One-hundred broilers were divided into ten groups (control (CNT); AF; NS; TMQ; BNT; AF+TMQ; AF+NS; AF+BNT; AF+BNT+NS; AF+BNT+TMQ) and fed for 28 d. AF, TMQ, NS and BNT were added to diets at levels of 2 mg/kg, 300 mg/kg, 50 g/kg and 10 g/kg respectively.4. The addition of AF to the diet decreased AKR7A2 and Nrf2 levels dramatically, but increased caspase-3 (P < 0.01). TMQ, NS and BNT additions to the diet eliminated all negative effects caused by AF (P < 0.01); and AKR7A2 and Nrf2 were further raised in TMQ and NS groups when compared to the control group. TMQ and NS showed a positive effect on detoxification parameters when given together with BNT.5. Supplementation with NS and TMQ enhanced AF detoxification via the AFAR pathway, by increasing AKR7A2 and Nrf2 levels, in addition to reducing hepatocyte apoptosis.

Diagnosing subclinical facial eczema in cattle: does combining liver enzyme tests increase the accuracy of diagnosis?

AIMS: To assess whether adding glutamate dehydrogenase (GDH) activity measurements to measurements of gamma-glutamyl transferase (GGT) activity appreciably increases the accuracy of diagnosis of subclinical facial eczema (FE) in cattle. METHODS: As part of a larger study on the impact of FE on productivity, GGT and GDH activities were measured in serum samples collected from 426 cattle from one dairy farm in the Taranaki region in April 2018. Bayesian latent class analysis was then used to estimate herd prevalence of subclinical FE as well as the specificity and sensitivity of the activity in serum of GGT or GDH alone, and of GGT and GDH activities combined, as diagnostic tests for subclinical FE. RESULTS: The latent class analysis estimated the true prevalence of subclinical FE in the study population as 47.5 (95% probability interval (PI) = 38.3-55.3)%. There was no evidence of any clinically relevant difference between GGT and GDH activities as predictors of subclinical FE; the difference between the areas under the receiver operating characteristic curves for the two measures was 0.005 (95% PI = -0.02 to -0.03). Using the two tests in parallel, with a threshold of 50 IU/L for GGT and 225 IU/L for GDH resulted in specificity and sensitivity of >95%, markedly increasing the accuracy of diagnosis of subclinical FE compared to using GGT or GDH alone at any threshold. CONCLUSIONS AND CLINICAL RELEVANCE: In this herd, combining the two tests resulted in a clinically relevant improvement in the accuracy of diagnosis of subclinical FE compared to using either test alone, which if used at the individual level will result in fewer cattle being assigned the wrong FE status. This will also apply at the herd level, with combined testing producing fewer false-positive herd test results than using one enzyme alone. This is particularly important for monitoring the efficacy of FE control measures when the expectation should be that the proportion of cattle with FE is very low.

The Efficacy of a Smectite-Based Mycotoxin Binder in Reducing Aflatoxin B1 Toxicity on Performance, Health and Histopathology of Broiler Chickens.

The aim of the experiment was to investigate the efficacy of a smectite-based clay binder (Toxo-MX) in reducing the toxicological effects of aflatoxin B1 (AFB1) in commercial broiler chickens. A total of 450 one-day old male broiler chickens were randomly allocated into three treatment groups with ten replicates of 15 birds each in a 42-day feeding experiment. The dietary treatments included a negative control (NC, a basal diet with no AFB1 and binder), a positive control (PC, a basal diet contaminated with 500 ppb of AFB1) and a smectite-based mycotoxin binder(Toxo-MX, PC with smectite clay binder). AFB1 challenge resulted in 14 to 24% depression in growth performance, elevated levels of aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT), organ enlargement and immuno-suppression.As compared to PC, feeding of Toxo-MX improved the final weight (15%; p < 0.0001), average daily gain (ADG) (15%; p < 0.001) and feed efficiency of broilers (13%; p < 0.0003) but did not have any effects on liver enzyme activities. Supplementation of smectite claysignificantly increased serum globulin levels and reduced the weight of the liver (p < 0.05) as compared to AFB1-fed broiler chickens. The severity of lesions (inflammatory and degenerative changes) observed in the liver, kidney, heart, pancreas, and lymphoid organs in PC birds was reduced by feeding smectite clay. The immuno-suppression caused by AFB1 was moderately ameliorated in Toxo-MX groupby stimulating the production of antibodies against IBD at day 42 (p < 0.05). In conclusion, dietary supplementation of a smectite-based mycotoxin binder to the diet containing AFB1 improved growth performance, reduced toxicological effects in liver and improved humoral immune response in broilers, suggesting its protective effect against aflatoxicosis.

Occurrence of Zearalenone and Its Metabolites in the Blood of High-Yielding Dairy Cows at Selected Collection Sites in Various Disease States.

Zearalenone (ZEN) and its metabolites, alpha-zearalenol (α-ZEL) and beta-zearalenol (ß-ZEL), are ubiquitous in plant materials used as feed components in dairy cattle diets. The aim of this study was to confirm the occurrence of ZEN and its selected metabolites in blood samples collected from different sites in the hepatic portal system (posthepatic-external jugular vein EJV; prehepatic-abdominal subcutaneous vein ASV and median caudal vein MCV) of dairy cows diagnosed with mastitis, ovarian cysts and pyometra. The presence of mycotoxins in the blood plasma was determined with the use of combined separation methods involving immunoaffinity columns, a liquid chromatography system and a mass spectrometry system. The parent compound was detected in all samples collected from diseased cows, whereas α-ZEL and ß-ZEL were not identified in any samples, or their concentrations were below the limit of detection (LOD). Zearalenone levels were highest in cows with pyometra, where the percentage share of average ZEN concentrations reached 44%. Blood sampling sites were arranged in the following ascending order based on ZEN concentrations: EJV (10.53 pg/mL, 44.07% of the samples collected from this site), ASV (14.20 pg/mL, 49.59% of the samples) and MCV (26.67 pg/mL, 67.35% of the samples). The results of the study indicate that blood samples for toxicological analyses should be collected from the MCV (prehepatic vessel) of clinically healthy cows and/or cows with subclinical ZEN mycotoxicosis. This sampling site increases the probability of correct diagnosis of subclinical ZEN mycotoxicosis.

Efficacy of phytobiotic and toxin binder feed additives individually or in combination on the growth performance, blood biochemical parameters, intestinal morphology, and microbial population in broiler chickens exposed to aflatoxin B1.

This experiment was conducted to investigate the effects of phytobiotic and antifungal feed additives on the growth performance, blood parameters, intestinal morphology, and cecal microbiota activity of broiler chickens under aflatoxicosis challenge. A total of 250 one-day-old Ross 308 broiler chicks (mixed sex) were reared on the littered floor with a completely randomized design by five treatments and five replicates for 35 days. Treatments included positive control (without AFB1), negative control-AFB1 (1 ppm), negative control-phytobiotic (Entex, 0.5 kg/t), negative control-Mycofix Plus (0.5 kg/t), and negative control-phytobiotic + Mycofix Plus. Dietary phytogenic and toxin binder improved body weight gain and feed conversion ratio of broiler chickens (p<0.05). Serum concentration of AST increased in broilers which received AFB1 without additives, while the blood concentration of total protein decreased (p<0.05). In jejuna morphometric indices, it was observed that the broiler chickens fed phytobiotic additive in combination with toxin binder had a greater villus length and crypt depth (p<0.05). Dietary treatments had no significant effect on the cecal microbial population in broiler chickens. In conclusion, the present results indicated that phytobiotic and toxin binder supplement improved growth performance and intestinal morphology of broiler chickens exposed to AFB1 challenge.

Toxic Effect of Aflatoxins in Dogs Fed Contaminated Commercial Dry Feed: A Review.

Since its first patent (1897), commercial dry feed (CDF) for dogs has diversified its formulation to meet the nutritional needs of different breeds, age, or special conditions and establish a foundation for integration of these pets into urban lifestyles. The risk of aflatoxicosis in dogs has increased because the ingredients used to formulate CDF have also proliferated, making it difficult to ensure the quality required of each to achieve the safety of the entire CDF. This review contains a description of the fungi and aflatoxins detected in CDF and the ingredients commonly used for their formulation. The mechanisms of action and pathogenic effects of aflatoxins are outlined; as well as the clinical findings, and macroscopic and microscopic lesions found in aflatoxicosis in dogs. In addition, alternatives for diagnosis, treatment, and control of aflatoxins (AF) in CDF are analyzed, such as biomarkers of effect, improvement of blood coagulation, rate of elimination of AF, control of secondary infection, protection of gastric mucosa, reduction of oxidative stress, use of chemo-protectors, sequestrants, grain-free CDF, biocontrol, and maximum permitted limits, are also included.

Development of a genetic evaluation for hair shedding in American Angus cattle to improve thermotolerance.

BACKGROUND: Heat stress and fescue toxicosis caused by ingesting tall fescue infected with the endophytic fungus Epichloë coenophiala represent two of the most prevalent stressors to beef cattle in the United States and cost the beef industry millions of dollars each year. The rate at which a beef cow sheds her winter coat early in the summer is an indicator of adaptation to heat and an economically relevant trait in temperate or subtropical parts of the world. Furthermore, research suggests that early-summer hair shedding may reflect tolerance to fescue toxicosis, since vasoconstriction induced by fescue toxicosis limits the ability of an animal to shed its winter coat. Both heat stress and fescue toxicosis reduce profitability partly via indirect maternal effects on calf weaning weight. Here, we developed parameters for routine genetic evaluation of hair shedding score in American Angus cattle, and identified genomic loci associated with variation in hair shedding score via genome-wide association analysis (GWAA). RESULTS: Hair shedding score was moderately heritable (h2 = 0.34 to 0.40), with different repeatability estimates between cattle grazing versus not grazing endophyte-infected tall fescue. Our results suggest modestly negative genetic and phenotypic correlations between a dam's hair shedding score (lower score is earlier shedding) and the weaning weight of her calf, which is one metric of performance. Together, these results indicate that economic gains can be made by using hair shedding score breeding values to select for heat-tolerant cattle. GWAA identified 176 variants significant at FDR < 0.05. Functional enrichment analyses using genes that were located within 50 kb of these variants identified pathways involved in keratin formation, prolactin signalling, host-virus interaction, and other biological processes. CONCLUSIONS: This work contributes to a continuing trend in the development of genetic evaluations for environmental adaptation. Our results will aid beef cattle producers in selecting more sustainable and climate-adapted cattle, as well as enable the development of similar routine genetic evaluations in other breeds.

Effect of Folic Acid Supplementation and Dietary Protein Level on Growth Performance, Serum Chemistry and Immune Response in Weanling Piglets Fed Differing Concentrations of Aflatoxin.

Effects of folic acid and protein levels on growth and serum chemistry in pigs fed aflatoxin were determined in two experiments. Increasing aflatoxin (250 to 800 ppb) decreased (P < 0.05) weight gain and feed intake for both of the 35-day trials. In Experiment 1, increasing aflatoxin (0, 250, 500 ppb), increased linearly (P < 0.05) aspartate aminotransferase (AST), alkaline phosphatase (ALKP) and ɣ-glutamyl transferase (GGT). Folic acid (0, 2.0, 5.0, 12.5 ppm) increased linearly (P < 0.05) serum K, Ca, P, Mg, and AST with the largest effect observed at 12.5 ppm. Folic acid decreased (P < 0.05) blood urea nitrogen (BUN): creatinine and Na:K. In Experiment 2, aflatoxin (800 ppb) increased (P < 0.05) glucose and GGT, and decreased (P < 0.05) Na:K and albumin:globulin. Increasing protein from 15 to 18% elevated BUN: creatinine (P < 0.05), albumin: globulin (P < 0.05), albumin (P < 0.05) and ALKP (P < 0.05). Folic acid (2 ppm) elevated (P < 0.05) BUN, and interacted with both aflatoxin (P < 0.10) and protein (P < 0.05) on BUN. Adding folic acid to aflatoxin contaminated diets improved some measures of clinical chemistry in Experiment 1 but not traditional growth performance measures. The higher protein level reduced the effects of aflatoxicosis on growth.

Ruminant Mycotoxicosis: An Update.

This review focuses on factors associated with mold production in feedstuffs and major mycotoxins affecting ruminants in North America. Ruminants are often considered less sensitive to mycotoxins owing to rumen microflora metabolism to less toxic compounds. However, ruminants occupy wide agricultural niches that expose animals to diverse toxins under widely different environmental and nutritional conditions. Often the moldy and potentially highly contaminated feeds end up at feedlots. Less than optimal feedstuffs creating suboptimal rumen microbial flora could result in decreased ruminal capacity to detoxify certain mycotoxins and adverse effects. Numerous mycotoxins and clinical effects in ruminants are discussed.

Horses fed meal contaminated with mycotoxins performing short-term exercises / Efeitos das micotoxinas na performance de equinos submetidos a exercícios de curta duração

This research was carried out to evaluate the effect of mycotoxins on the performance of horses through physiological parameters, and hematology and serum biochemistry analyses. The essay lasted 40 days, with 12 days for adaptation and 28 days of experimentation. In the experimental stage, the horses were distributed in a completely randomized design, with three treatments with four animals each. The treatments used were 0 (control), 50 ppb and 100 ppb of Aflatoxin B1 (AFB1) added to a concentrate in a basal diet. The basal diet contained mycotoxins from feedstuffs naturally contaminated. The exercise test was performed over the 21th day of the experimental stage. The exercise consisted in an interval training test with a warm-up of 17 mins at a trot followed by three gallops of 450m/min. The heart rate was monitored between the gallops. Before the exercise test and immediately after the third gallop, the physiological and blood parameters were evaluated, and continued up to 48 hours after the exercise. The results of the physiological, hematological and biochemical parameters were submitted to analysis of variance (ANOVA) and compared by the Tukey test at 5% of significance. The presence of AFB1 in the diet influenced the alkaline phosphatase activity, which presented higher values in horses fed diet with inclusion of 100 ppb AFB1, suggesting a hepatotoxic activity associated with the others mycotoxins naturally present in the feedstuffs.(AU)

Esta pesquisa foi conduzida para avaliar o efeito de micotoxinas no desempenho de equinos com avaliações fisiológicas e análises hematológicas e da bioquímica sérica. O ensaio durou 40 dias, com 12 dias de adaptação e 28 dias de experimentação. Na fase experimental, os equinos foram distribuídos em delineamento inteiramente casualizado em três tratamentos, com quatro animais cada. Os tratamentos utilizados foram 0 (controle), 50 ppb e 100 ppb de Aflatoxina B1 (AFB1) adicionada ao concentrado de uma dieta basal. A dieta basal continha alimentos naturalmente contaminados por micotoxinas. O teste de desempenho foi executado no 21º dia da fase experimental por meio de teste intervalado consistindo em aquecimento ao trote por 17 minutos, seguido de três galopes de 450m/min. A frequência cardíaca (FC) foi monitorada entre os galopes. Antes do exercício e imediatamente após o terceiro galope, os parâmetros fisiológicos e sanguíneos foram avaliados e continuaram sendo monitorados até 48 horas após o exercício. Os resultados dos parâmetros fisiológicos, hematológicos e bioquímicos foram submetidos à análise de variância (ANOVA) e comparados pelo teste de Tukey a 5% de significância. A presença de AFB1 na dieta influenciou a atividade da fosfatase alcalina, que apresentou valores mais elevadas na dieta com inclusão de 100 ppb de AFB1, sugerindo uma atividade hepatotóxica associada às outras micotoxinas naturalmente presentes nos alimentos.(AU)

Failure of diplodiatoxin to induce diplodiosis in juvenile goats.

Diplodiosis is an important neuromycotoxicosis of ruminants in South Africa when grazing on harvested maize fields in winter. It is believed to be caused by mycotoxin(s) synthesised by Stenocarpella (Diplodia) maydis. Although several metabolites have been isolated from S. maydis culture material, none of these have been administered to ruminants to reproduce the disease. The objectives of this study were to isolate diplodiatoxin and to administer it to juvenile goats. Diplodiatoxin, considered as a major metabolite, was purified from S. maydis-infected maize cultures (Coligny 2007 isolate). Following intravenous administration of 2 mg and 4 mg diplodiatoxin/kg body weight for five consecutive days to two juvenile goats, no clinical signs reminiscent of diplodiosis were observed. Based on previous experimental results and if diplodiatoxin was the causative compound, the dosage regimen employed was seemingly appropriate to induce diplodiosis. In addition, intraruminal administration of 2 mg/kg diplodiatoxin to one goat for three consecutive days also did not induce clinical signs. It appears as if diplodiatoxin alone is not the causative compound. Other metabolites and/or mixtures of diplodiatoxin and other mycotoxins, when available in sufficient quantities, should also be evaluated.

Toxic tall fescue grazing increases susceptibility of the Angus steer fecal microbiota and plasma/urine metabolome to environmental effects.

Impaired thermoregulation and lowered average daily gains (ADG) result when livestock graze toxic endophyte (Epichloë coenophialum)-infected tall fescue (E+) and are hallmark signs of fescue toxicosis (FT), a disease exacerbated by increased temperature and humidity (+temperature-humidity index; +THI). We previously reported FT is associated with metabolic and microbiota perturbations under thermoneutral conditions; here, we assessed the influence of E+ grazing and +THI on the microbiota:metabolome interactions. Using high-resolution metabolomics and 16S rRNA gene sequencing, plasma/urine metabolomes and the fecal microbiota of Angus steers grazing non-toxic or E+ tall fescue were evaluated in the context of +THI. E+ grazing affected the fecal microbiota profile; +THI conditions modulated the microbiota only in E+ steers. E+ also perturbed many metabolic pathways, namely amino acid and inflammation-related metabolism; +THI affected these pathways only in E+ steers. Integrative analyses revealed the E+ microbiota correlated and co-varied with the metabolomes in a THI-dependent manner. Operational taxonomic units in the families Peptococcaceae, Clostridiaceae, and Ruminococcaceae correlated with production parameters (e.g., ADG) and with multiple plasma/urine metabolic features, providing putative FT biomarkers and/or targets for the development of FT therapeutics. Overall, this study suggests that E+ grazing increases Angus steer susceptibility to +THI, and offers possible targets for FT interventions.

Physiological response, function of sweat glands, and hair follicle cycling in cattle in response to fescue toxicosis and hair genotype.

Fescue toxicosis is a syndrome that results when cattle consume toxic endophyte-infected tall fescue. The objective of this study was to compare the response in physiological variables, sweat gland function, hair follicle cycling, and gene expression to feeding a total mixed ration that included tall fescue haylage and tall fescue seed containing a toxic endophyte (EI) or tall fescue haylage containing a nontoxic novel endophyte (EN) in beef heifers (Angus × Senepol heifers, n = 31) with 2 different hair genotypes. Numbers in each subgroup were as follows: novel endophyte, heterozygous slick (EN-S; n = 8), novel endophyte, homozygous hairy (wild type, EN-W; n = 7), endophyte-infected, heterozygous slick (EI-S; n = 10), and endophyte-infected, homozygous hairy (wild type, EI-W; n = 6). Physiological measurements were taken weekly for 7 wk. Data were analyzed using the MIXED procedure of SAS including dietary fescue treatment (EN vs. EI) and hair genotype (S vs. W) as main effects, day as a repeated measure, and temperature-humidity index (THI) as a covariate. Skin biopsies were taken before treatment initiation and on day 37 of treatment. Average surface temperature (ST) increased as the THI increased (P < 0.0001). Average ST was greater (P < 0.01) for animals fed EI than for animals fed the EN fescue diet, and greater (P < 0.01) for animals with the W genotype compared with animals with the S genotype. The difference between heifers with the S and W genotype was greater at greater THI (genotype × day interaction, P < 0.01). Transepidermal water loss (TEWL) was greater (P < 0.05) for animals with the S genotype compared with the W genotype and greater (P < 0.05) for heifers with the S genotype than for heifers with the W genotype when fed EI (36.7, 38.5, 30.0, and 38.7 g/m2 per hour for EN-W, EN-S, EI-W, and EI-S, respectively). The fraction of follicles in telogen in plucked hair samples for heifers fed EI was greater for animals with the S genotype than the W genotype (fraction in telogen: 0.456, 0.565, 0.297, 0.702 for EN-W, EN-S, EI-W, and EI-S, respectively; diet × genotype interaction, P < 0.05). Fraction of follicles in anagen was the opposite. EI fescue resulted in increased ST, changes in hair follicle cycling that support greater hair growth, and decreased TEWL for heifers with the W genotype compared with S genotype, suggesting greater heat stress in response to EI.

Nutrient stability in mould-infested feed and mitigating effect of dietary supplemental vitamins in brown laying hens.

A 10-week study was conducted to assess the impact of mould infestation on nutrient stability of feed and the mitigating effect of supplemental tocopherol, retinol or a multivitamin on performance and hepatic histology of ISA Brown laying chickens. Two batches of corn were obtained: the aflasafe corn used in preparing control diet and corn with physical evidence of mould used in preparing diets 2 to 5 containing no supplemental vitamin, tocopherol, retinol or a branded multivitamin supplementations respectively. One hundred and fifty (150) laying chickens used were completely randomized into five dietary treatments with three replicates of 10 birds each. Results showed that there was gross instability in the nutrients of mouldy maize. The activities of the fungi depleted both protein and lipid contents by 11.54% and 12.72% respectively while crude fibre content rose by 31.7%. There was substantial drop in both retinol and tocopherol while aflatoxin content rose to 267 µg in mouldy corn and 118 µg in the mouldy diets. Feed intake was significantly (P < 0.05) reduced and consequently depressed (P < 0.05) egg production and feed efficiency. Egg quality differs (P < 0.05) in shell thickness and yolk colour. Proliferation of biliary duct epithelium, hepatic degeneration, cellular infiltration, hyper-cellularity or dilation of the sinusoidal spaces characterized livers of birds on mouldy corn diets while supplementation with vitamins subverted mycosis and aflatoxicosis as evidenced by normal-to-mild congestion of hepatocytes. It was concluded that mould contamination in feed compromised feed nutritive values, reduced bird performance and adversely impaired the liver of the experimental birds while tocopherol, retinol or a multivitamin supplementation relapses the damaging potential of mould and mycotoxin differently.

Toxicopathological effects of feeding aflatoxins B1 in broilers and its ameliosration with indigenous mycotoxin binder.

Mycotoxicosis is the second most important problem faced by the Pakistan poultry industry, after high feed prices. The present experimental study was designed to investigate the toxicopathological effects of aflatoxin B1 (AFB1) in commercial broiler chicks and its amelioration with locally produced mycotoxin binder. Total of 125 broiler chicks was divided into five equal groups (A-E). Group A served as negative control, group B (300 µg AFB1/kg feed) as positive control, group C (300 µg AFB1/kg + Local Mycotoxin Binder (LMB), 1 g/kg feed), group D (300 µg AFB1/kg + 2 g LMB/kg feed), and group E (300 µg AFB1/kg + Commercial Mycotoxin Binder (CMB), 2 g/kg of feed). Parameters studied included mortality, feed intake, bodyweights, absolute and relative organ weights, and gross and microscopic lesions in visceral organs. Clinical signs including alertness, fecal consistency, and feather shine were significantly lower in group B compared with control group A. The feed intake of 2 g/kg LMB treated group was significantly higher than that of the positive control group B. Also mean bodyweights of group D birds was higher than that of group B birds indicating an ameliorative effect of LMB. Histopathological results showed that moldy feed produced necrotic changes in the liver and kidneys in group B birds. However, in group D and E birds, the hepatic and renal parenchyma was normal, showing a protective effect of LMB. In the present study, a higher dose of LMB (2 g/kg) in group D showed higher bodyweights and feed intake. In group D, birds hepatic and renal parenchyma was also normal. The results suggested that local mycotoxin binder ameliorated the toxicopathological effects of AFB1 in mortality, feed intake, bodyweights, organ weights and, gross and microscopic lesions in visceral organs. These ameliorative effects of LMB were dose-dependent. The results of the present study concluded that AFB1 intoxication leads to decrease in bodyweights, feed intake in dose-related manner. The mortality was also dose-dependent. Gross and microscopic changes in the aflatoxin groups were more pronounced, however, all these deleterious effects were ameliorated in higher dose of LMB (group D) and CMB (group E). In group C, these deleterious effects were partially ameliorated. Local mycotoxin binder is an economical solution for aflatoxicosis problem, making poultry production more cost-effective.

Spongy Myelinopathy in Newborn Beef Calves Associated with Consumption of Corn Infected with Stenocarpella maydis.

Stillbirth and perinatal mortality with neurological signs and lesions were diagnosed in two calves following ingestion by their dams of corn infected with Stenocarpella maydis during the third trimester of gestation. Grossly, the brain and spinal cord were unremarkable. Microscopically, diffuse severe status spongiosis of the white matter was detected in the cerebral hemispheres, brainstem, spinal cord and cerebellum. To the best of our knowledge this is the first pathological description of congenital disease in calves associated with the consumption of S. maydis-infected corn; the findings resemble those reported for the naturally occurring and experimentally induced disease in lambs.