Effect of fungicides on Fusarium ear blight and mycotoxin accumulation in winter wheat (<i>Triticum aestivum</i> L.)

In order to determine the effect of a range of fungicide products, dose rate and time of application on the development of Fusarium head blight (FHB) and mycotoxin contamination of winter wheat, a series of field experiments (1998-2001) were carried out. A mixture of the fungicides metconazole+azoxystrobin provided the most significant reduction of (FHB) severity (63%) in comparison with control treatments followed by mectonazole (39%) and tebuconazole (45%) applied at both full and half the manufacturers recommended dose rate. Quantification of Tri5 DNA and deoxynivalenol (DON) concentration in harvested grain indicated that metconazole and tebuconazole were the most efficacious fungicides at reducing colonisation of grain by trichothecene-producing Fusarium species and DON content. Azoxystrobin had no effect on Tri5 DNA and DON concentration in grain, but significantly reduced the incidence of Microdochium nivale infected wheat grain. Fungicides applied early in the growing season (GS 31 and 39) were less effective at controlling disease than those applied later in the season (GS 39 and 59). Indeed, it was evident that the timing of fungicides was critical for the effective control of FHB and DON with the best control achieved when fungicides were applied either two days before or two days after the artificial inoculation of wheat ears with FHB causing pathogens. Regression analysis on field trial data revealed that fungicides were able to influence DON content in harvested wheat grain by affecting the extent of grain colonisation by mycotoxin producing species. Since published literature has suggested that fungicides can directly influence DON contamination by imparting a stress influence on FHB pathogens, glasshouse studies were undertaken to determine the effect of a range of dose rates of the fungicides azoxystrobin and metconazole against FHB and DON in wheat plants inoculated with either Fusarium culmorum or F. graminearum. Results revealed that metconazole was effective at reducing FHB, Tri5 DNA and DON and that a rate response was observed as dose rate was increased from one quarter to double the manufacturer's recommended dose rate. Although azoxystrobin reduced FHB, Tri5 DNA and DON content compared to untreated controls, no dose rate response was observed. Regression analysis of glasshouse data supported those obtained from field studies, suggesting that fungicides are able to influence DON content indirectly by affecting the extent of grain colonisation by F. culmorum and F. graminearum. Further glasshouse studies were conducted to determine the interactions between Alternaria tenuissima, Cladosporium herbarum, M. nivale and F. culmorum and the effect of fungicides on these interactions. Introducing C. herbarum or M. nivale to wheat ears at GS 57, before inoculation with F. culmorum at GS 65, resulted in a significant increase in FHB severity, Tri5 DNA and DON concentration in grain. Applying azoxystrobin to wheat ears after the introduction of M. nivale at GS 57, increased DON concentration in grain by 56%. The significance of interactions between saprophytic fungi, M. nivale and Fusarium species on fungicides efficacy against FHB and DON is discussed

The effect of wheat cultivars on the growth performance and energy retention of broiler chickens

The nutritive values of twelve samples of different UK wheat cultivars from two different growing years were assessedA. serieso f chicken feeding experimentsw ere conducted to examine the relationships between chemical composition, grain quality and energy content of the wheat samples and the growth performance of broiler chickens when fed these wheat samples as part of nutritionally complete diets. The efficiency of utilization of apparent metabolisable energy (AMEn) of wheat samples as a source of net energy (NE) was studied. Step-wisc multiple regression analysis indicated that the content of total starch in the wheat samples and the arnylosea: mylopectin ratio in the starch were the main predictors of growth, feed intake and FCR of the broilers. Increasing starch and arnylose content in the wheat cultivar samples gave increasing weight and feed intakes. The Hagberg falling number was also significantly (P0.05) differences in broiler growth performance. The influence of different amylose: amylopectin ratios on the physical nature of the starch granule may therefore be more important than their effects in changing the total dietary supply of those starch components. Although the net energy concentration of a wheat sample was related (p<0.05, r2=0.42) to its determined AME, there was still unexplained variation (about 60%) in the cilicicncy of utilization of AME as a source of NE. A proportion of this variation was, however, explained (p<0.05, r2=0.40) by differences in the water-extract viscosity of the wheat samples. Different ileal viscosities, due to feeding different wheat cultivars, may result in variation in the amount of intestinal fermentation of nutrients and so altcr the NENE ratio of whcat-based diets

Manipulation of plasma myo-inositol in broiler chickens: effect on growth performance, dietary energy, nutrient availability, and hepatic function

This study investigated the effects of graded levels of myo-inositol (INS) in diets containing 2 levels of available P on growth performance, nutrient retention, liver N, fat and Vitamin E contents, INS and alkaline phosphatase (ALP) concentrations in blood plasma. A total of 120 male Ross 308 broilers were allocated to 60 small floor pens each holding 2 birds. Two basal mash diets were formulated to be nutritionally adequate for chicks at that age, with one diet designed to have the recommended available P content (RP) (4.8 g/kg non-phytate P) and the other diet containing low available P (LP) (2.5 g/kg non-phytate P). The 2 basal diets were split in 3 batches each and 2 of the batches were supplemented with INS at 3.0 and 30 g/kg diet, with the remaining batch of each basal diet not supplemented, giving a total of 6 experimental diets. Diets were fed ad libitum to 10 pens from 7 to 21 d age following randomization. Feeding RP diets improved (P 0.05) influence bird growth, dietary AME, or nutrient retention coefficients. Feeding INS linearly increased (P 0.05) the endogenous losses (measured as sialic acid concentration) in excreta. Dietary INS did not influence (P > 0.05) the hepatic Vitamin E concentration but increased (P < 0.001) the ALP in the blood of birds fed 30 g/kg INS. In conclusion, highlevel dietary INS supplementation did not affect bird growth performance, mineral availability, and endogenous losses, and there were no interactions between INS and P

Plant Extracts, Energy, and Immune Modulation in Broilers

This chapter presents information obtained from experiments involving male Ross 308 broiler chickens on the effects of a standardised combination of plant extracts (PE) including carvacrol, cinnamaldehyde and capsicum oleoresin, on bird performance, hepatic antioxidant concentration and immunomodulation. Birds were reared under industry-recognised environments and were fed one of four diets. There were two control diets based on either wheat or maize, formulated to be iso-energetic and iso-nitrogenic. The other two diets were the control diets supplemented with 100 g per tonne of PE, respectively. Feeding PE improved dietary feed efficiency, dietary net energy and hepatic antioxidant contents of the birds, but did not change dietary metabolisable energy (ME). Overall, feeding PE reduced the mRNA transcript levels of three cytokines (IL-12B, IFN-G, and IL-6) and the marker CD 40 LG in caecal tonsils. Dietary PE may maximise the nutritional value of feed through improving gut health by reducing intestinal inflammation. Their mode of action is associated with improved dietary energy availability, immune status and hepatic antioxidant contents of the birds. However, studies that have focused solely on the effect of PE on ME alone may not have detected their full benefit to improve the efficiency of broiler meat production

Effect of wheat distillers dried grains with solubles and exogenous xylanase on laying hen performance and egg quality

Despite the rapid increase in the use of wheat distillers dried grains with solubles (DDGS) within the poultry sector, little information is available on how the long-term feeding of this by-product will affect the performance of laying hens. This experiment examined the effect of wheat DDGS, with and without exogenous xylanase on dietary apparent metabolizable energy (AME), total tract dry matter retention (DMR), nitrogen retention (NR), fat digestibility (FD) coefficients, feed intake (FI), bodyweight gain (BWG), eggs laid, mean egg weight, egg mass output, and egg quality characteristics including albumin height (AH), Haugh units (HU), yolk color, eggshell strength, and thickness. A total of 320 Hy-Line brown laying hens were randomly allocated to 80 enriched layer colonies (groups of 4). A total of 2 control wheat-soybean meal-based diets were formulated to contain 11.60 MJ/kg. One of the diets contained 300 g/kg wheat DDGS, while the other was DDGS free, with a respective crude protein content of 171.1 g/kg and 166.5 g/kg. Both diets were divided by 2 and half of them were supplemented with 2,500 U/kg of xylanase, resulting in 4 diets in total. Data was analyzed as a 2 × 2 factorial arrangement of treatments with analysis of variance (ANOVA). Diets were fed ad libitum from 17 to 43 wk of age and data was collected from 23 to 43 wk. The inclusion of wheat DDGS reduced (P < 0.001) dry matter retention (DMR), FI, BWG, eggs laid, mean egg weight, and egg mass. However, xylanase supplementation improved AME and NR in diets containing wheat DDGS and FD in diets without DDGS (DDGS × xylanase, P < 0.05) and tended to improve (P < 0.10) BWG and egg mass output. For egg quality measurements, the inclusion of DDGS improved (P = 0.046) HU values, eggshell strength (P < 0.001), and increased (P < 0.001) yolk color intensity. This experiment showed xylanase can be used to improve the AME and NR of DDGS-based diets. However, the long-term feeding of 300 g/kg wheat DDGS negatively impacts the productive performance of hens

Partioning of dietary energy of chickens fed maize or wheat-based diets with and without a commercial blend of phytogenic feed additives

The aim of the study was to investigate the effects of a standardized mixture of a commercial blend of phytogenic feed additives containing 5% carvacrol, 3% cinnamaldehyde, and 2% capsicum on utilization of dietary energy and performance in broiler chickens. Four experimental diets were offered to the birds from 7 to 21 d of age. These included 2 basal control diets based on either wheat or maize that contained 215 g CP/kg and 12.13 MJ/kg ME and another 2 diets using the basal control diets supplemented with the plant extracts combination at 100 mg/kg diet. Each diet was fed to 16 individually penned birds following randomization. Dietary plant extracts improved feed intake and weight gain (P 0.05) but improved (P < 0.05) dietary NE by reducing the heat increment (P < 0.05) per kilogram feed intake. Feeding phytogenics improved (P < 0.05) total carcass energy retention and the efficiency of dietary ME for carcass energy retention. The number of interactions between type of diet and supplementary phytogenic feed additive suggest that the chemical composition and the energy to protein ratio of the diet may influence the efficiency of phytogenics when fed to chickens. The experiment showed that although supplementary phytogenic additives did not affect dietary ME, they caused a significant improvement in the utilization of dietary energy for carcass energy retention but this did not always relate to growth performance

Evaluation of novel protease enzymes on growth performance and apparent ileal digestibility of amino acids in poultry: enzyme screening

Three experiments were conducted to evaluate eight neutral and six acid proteases on growth performance and apparent ileal amino acid digestibility (AID) of poults (Experiment 1) or chicks (Experiments 2 and 3). Two basal diets were formulated: a nutrient adequate positive control (PC), which met or exceeded the nutrient requirements for poults (Experiment 1) or chicks (Experiments 2 and 3) and a negative control (NC) formulated to achieve 85% (Experiments 1 and 2) or 80% (Experiments 3) of the requirement for protein and amino acids. Phytase was included in all diets to provide 500 phytase units (FTU)/kg and xylanase was included in all diets to provide 10,000 (Experiments 1 and 2) or 16,000 (Experiments 3) xylanase units (BXU)/kg. Proteases were supplemented in the NC diet at an equivalent amount of enzyme protein to create 16 experimental diets. There were five birds/pen and 10 replicate pens per treatment in each experiment. In experiment 1, birds fed the PC diet gained more (P < 0.05) than birds fed the NC. There were no differences in growth performance in birds fed the PC or NC in experiments 2 or 3. In all three experiments, birds fed the NC supplemented with neutral protease 1 had reduced (P < 0.05) feed intake (FI) or body weight gain (BWG) and increased (P < 0.05) feed conversion ratio (FCR) compared with birds fed the NC. Birds fed the NC diet supplemented with neutral protease 3, 7 (Experiment 1), or acid protease 4 (Experiment 3) had increased (P < 0.05) FCR and birds fed neutral protease 6 (Experiment 2) had reduced (P < 0.05) BWG compared with birds fed the NC. Apparent ileal amino acid digestibility was improved (P < 0.05) with protease supplementation to the NC diets (Experiment 1 or 3), but this was dependent on the protease and the amino acid. In conclusion, novel protease supplementation improved AID of amino acids but this was not reflected in improvements in growth performance of poults or chicks

Exogenous tannase improves feeding value of a diet containing field beans (Vicia faba) when fed to broilers

A total of 72 male Ross 308 broilers were used in a study to investigate the effect of dietary tannase on apparent metabolisable energy (AME), coefficients of dry matter retention (DMR) and nitrogen retention (NR) and fat digestibility (FD) of a diet containing 300 g/kg field beans (Vicia faba). Growth performance variables and gastrointestinal tract development were also measured. Two treatments were used in this study: control (C) and C + 3400 tannase units (TU) per kg feed. Diets were formulated to be nutritionally adequate with the exception that the AME was lower than recommended (12.65 vs 12.97 MJ/kg, respectively). Inclusion of tannase increased AME by 0.4 MJ/kg DM. Tannase supplementation improved dietary DMR, NR and FD by 2.8%, 3.2% and 6.5%, respectively. Birds given tannase had 4.4% reduction in feed intake and 2.6% improvement in gain to feed ratio (P < 0.05). Compared to control diet, birds given tannase had reduced relative to body weight (%BW) proventriculus and gizzard and pancreas weights, 3.29% vs 3.09% and 0.47% vs 0.44%, respectively. The mechanisms of action of the studied enzyme require further elucidation

Immune modulation, growth performance, and nutrient retention in broiler chickens fed a blend of phytogenic feed additives

his study aimed to assess the effect of a commercial blend of phytogenic feed additives (PA), comprising 5% carvacrol, 3% cinnamaldehyde, and 2% capsicum oleoresin on the modulation of immune biomarkers of broiler chickens, their growth performance, dietary energy, and nutrient retention. Four-hundred day-old birds were assigned to one of four dietary treatments. Two control diets based on either wheat (WC) or maize (MC) were each given with and without PA at 100 g/t. Growth performance variables including feed intake (FI), weight gain (WG), and feed conversion ratio (FCR) were recorded. Dietary N-corrected apparent metabolizable energy (MEn), dry matter (DMR), nitrogen (NR), and fat retention (FR) coefficients were also determined. Gene expression of immune biomarkers (cytokines) were determined in caecal tonsil tissue from 21 d old birds. Expression of IL2, IL18, IL10, and IL17C in the caecal tonsils were upregulated (P 0.05) change in expression levels in birds fed MC diets. Feeding MC diets gave greater FI (P 0.05) by cereal type. Supplementary PA improved FI (P < 0.05), WG (P < 0.001), FCR (P < 0.05), MEn (P < 0.05), MEn: GE ratio (P < 0.05), and FR (P < 0.05). In conclusion, dietary inclusion of PA improved overall growth performance variables, energy, and nutrient retention and intestinal cytokine expression

The use of metabonomics to uncover differences between the small molecule profiles of eggs from cage and barn housing systems

Metabonomic techniques have been used to observe differences in the small molecule profiles of chicken eggs, to work towards the detection, and thus prevention, of fraud regarding the misrepresentation of egg farming systems. High Performance Liquid Chromatography-Quadrupole-Time-of-Flight-Mass Spectrometry (HPLC-Q-ToF-MS) was used to obtain profiles of the small molecules found in the yolks of eggs that were laid by hens in enriched cage systems, and in barn systems. Statistical analysis of these small molecule profiles, including the use of XCMS Online and multivariate statistics, was able to uncover differences between the yolks of cage and barn eggs. Several unidentified compounds were found to be present in significantly different abundances between cage and barn egg yolks and one of these compounds was tentatively identified, through the use of METLIN, as 1,2-dipalmitoyl-glycero-3-phosphocholine