Effects of Deoxynivalenol and Fumonisins on Broiler Gut Cytoprotective Capacity.

Mycotoxins are a crucial problem for poultry production worldwide. Two of the most frequently found mycotoxins in feedstuffs are deoxynivalenol (DON) and fumonisins (FUM) which adversely affect gut health and poultry performance. The current knowledge on DON and FUM effects on broiler responses relevant for gut detoxification, antioxidant capacity, and health is still unclear. The aim of this study was to assess a range of selected molecular intestinal biomarkers for their responsiveness to the maximum allowable European Union dietary levels for DON (5 mg/kg) and FUM (20 mg/kg) in broilers. For the experimental purpose, a challenge diet was formulated, and biomarkers relevant for detoxification, antioxidant response, stress, inflammation, and integrity were profiled across the broiler intestine. The results reveal that DON significantly (p < 0.05) induced aryl hydrocarbon receptor (AhR) and cytochrome P450 enzyme (CYP) expression mainly at the duodenum. Moreover, DON and FUM had specific significant (p < 0.05) effects on the antioxidant response, stress, inflammation, and integrity depending on the intestinal segment. Consequently, broiler molecular responses to DON and FUM assessed via a powerful palette of biomarkers were shown to be mycotoxin and intestinal site specific. The study findings could be highly relevant for assessing various dietary bioactive components for protection against mycotoxins.

Priming of intestinal cytoprotective genes and antioxidant capacity by dietary phytogenic inclusion in broilers.

The potential of a phytogenic premix (PP) based on ginger, lemon balm, oregano and thyme to stimulate the expression of cytoprotective genes at the broiler gut level was evaluated in this study. In particular, the effects of PP inclusion levels on a selection of genes related to host protection against oxidation (catalase [CAT], superoxide dismutase 1 [SOD1], glutathione peroxidase 2 [GPX2], heme oxygenase 1 [HMOX1], NAD(P)H quinone dehydrogenase 1 [NQO1], nuclear factor (erythroid-derived 2)-like 2 [Nrf2] and kelch like ECH associated protein 1 [Keap1]), stress (heat shock 70 kDa protein 2 [HSP70] and heat shock protein 90 alpha family class A member 1 [HSP90]) and inflammation (nuclear factor kappa B subunit 1 [NF-κB1], Toll-like receptor 2 family member B (TLR2B) and Toll-like receptor 4 [TLR4]) were profiled along the broiler intestine. In addition, broiler intestinal segments were assayed for their total antioxidant capacity (TAC). Depending on PP inclusion level (i.e. 0, 750, 1,000 and 2,000 mg/kg diet) in the basal diets, 1-d-old Cobb broiler chickens (n = 500) were assigned into the following 4 treatments: CON, PP-750, PP-1000 and PP-2000. Each treatment had 5 replicates of 25 chickens with ad libitum access to feed and water. Data were analyzed by ANOVA and means compared using Tukey's honest significant difference (HSD) test. Polynomial contrasts tested the linear and quadratic effect of PP inclusion levels. Inclusion of PP increased (P ≤ 0.05) the expression of cytoprotective genes against oxidation, except CAT. In particular, the cytoprotective against oxidation genes were up-regulated primarily in the duodenum and the ceca and secondarily in the jejunum. Most of the genes were up-regulated in a quadratic manner with increasing PP inclusion level with the highest expression levels noted in treatments PP-750 and PP-1000 compared to CON. Similarly, intestinal TAC was higher in PP-1000 in the duodenum (P = 0.011) and the ceca (P = 0.050) compared to CON. Finally, increasing PP inclusion level resulted in linearly reduced (P ≤ 0.05) expression of NF-κB1, TLR4 and HSP70, the former in the duodenum and the latter 2 in the ceca. Overall, PP inclusion consistently up-regulated cytoprotective genes and down-regulated stress and inflammation related ones. The effect is dependent on PP inclusion level and the intestinal site. The potential of PP to beneficially prime bird cytoprotective responses merit further investigation under stress-challenge conditions.

Dietary probiotic form modulates broiler gut microbiota indices and expression of gut barrier genes including essential components for gut homeostasis.

The probiotic form (PF) type and its dietary administration in combination or not with avilamycin (AV) were investigated for their effects on broiler gut microbiota and expression of genes relevant for gut barrier and gut homeostasis. Depending on PF type (i.e. no addition, viable, inactivated) and AV addition (no/yes), 450 one-day-old Cobb male broilers were allocated in 6 treatments (CON, CON + A, ViP, ViP + A, InP and InP + A) according to a 3 × 2 factorial arrangement with 5 replicates of 15 broilers each for 42 days. Significant interactions (PPF × AV  ≤ 0.05) between PF and AV administration were shown for the ileal mucosa-associated bacteria, the caecal digesta Lactobacillus spp., the molar ratio of the sum of valeric, hexanoic and heptanoic acids and the gene expressions of ileal and caecal IgA and ileal claudin 1. Avilamycin suppressed ileal digesta Lactobacillus spp. (PAV  < 0.001) and caecal digesta Clostridium perfringens subgroup (PAV  = 0.018) and modulated the intestinal fermentation intensity and pattern. The viable PF had the higher levels of ileal digesta Bacteroides spp. (PPF  = 0.021) and caecal digesta Lactobacillus spp. (PPF  = 0.038) compared with the other two PF. Probiotic form modulated the microbial metabolic activity in the ileum and caeca with the viable PF being the most noteworthy in terms of effects regarded as beneficial. Furthermore, the viable PF resulted in reduced expression of caecal Toll-like receptors TLR2B (PPF  = 0.026) and TLR4 (PPF  = 0.011) and transcription factor NFΚΒ1 (PPF  = 0.002), which could be considered as essential for limiting inflammation and preserving gut homeostasis. In conclusion, under non-challenge conditions, probiotic function was shown to depend on PF type and to a lesser degree on co-administration with AV. The importance of probiotic viability for the beneficial modulation of important gut components towards a reduced state of physiological inflammation has been highlighted.

Growth performance, nutrient digestibility, antioxidant capacity, blood biochemical biomarkers and cytokines expression in broiler chickens fed different phytogenic levels.

The effects of inclusion levels of a phytogenic feed additive (PFA), characterized by menthol anethol and eugenol, on broiler growth performance, nutrient digestibility, biochemical biomarkers and total antioxidant capacity (TAC) of plasma and meat, as well as on the relative expression of selected cytokines, were studied in a 42-d experiment. A total of 225 one-day-old male Cobb broiler chickens were assigned into 3 treatments, with 5 replicates of 15 chickens each. Chickens were fed maize-soybean meal basal diets following a 3 phase (i.e., starter, grower and finisher) feeding program. Depending on PFA inclusion level, treatments were: no PFA (PFA-0), PFA at 100 mg/kg (PFA-100) and PFA at 150 mg/kg (PFA-150). Feed and water were available ad libitum. Feed conversion ratio (FCR) during finisher phase was improved quadratically (P < 0.05) with increasing PFA level. Overall, increasing PFA level increased body weight gain (BWG) in a linear (P < 0.05) and quadratic (P < 0.05) manner with treatments PFA-100 and PFA-150 being greater (P < 0.05) compared with PFA-0. Total tract apparent digestibility of dry matter increased linearly (P < 0.05) and quadratically (P < 0.05) with increasing PFA level. The apparent metabolizable energy corrected for nitrogen (AMEn) also increased linearly (P < 0.05). Increasing PFA level resulted in a linear (P < 0.05) increase in blood plasma TAC. Expression of pro-inflammatory cytokine interleukin -18 (IL-18) was reduced linearly (P < 0.05) in spleen with increasing PFA level. In conclusion, PFA inclusion at 100 mg/kg diet positively influenced performance, whereas PFA inclusion at 150 mg/kg resulted in a stronger improvement in AMEn and plasma TAC. Finally, PFA inclusion resulted in a pattern of reduced pro-inflammatory biomarker IL-18 at spleen. Overall, this study provides evidence for the beneficial role of PFA as a natural growth and health promoter in broiler chickens that needs to be further confirmed in field studies.

Phytogenic Administration and Reduction of Dietary Energy and Protein Levels Affects Growth Performance, Nutrient Digestibility and Antioxidant Status of Broilers.

The aim of this study was to investigate the effect of reduced dietary energy (ME) and protein (CP) levels along with administration of a phytogenic feed additive (PFA) based on oregano, anise and citrus essential oils, on broiler growth performance, nutrient digestibility, meat and blood biochemical parameters and total antioxidant capacity (TAC). Depending on dietary ME and CP level down regulation compared to a corn-soybean meal basal diet A used as positive control, three diet types [A, B(=A-3%) and C(=A-6%)] were implemented. Depending on the inclusion or not of PFA at 125 mg/kg diet, 450 1-d old, male Cobb broilers were randomly allocated in six treatments according to a 3×2 factorial arrangement with 5 replicates of 15 broilers; A: diets formulated optimally to meet broiler nutrient requirements for maximizing protein content of meat for starter, grower and finisher growth periods; APh: A+PFA; B: suboptimal in ME and CP levels by 3%; BPh: B+PFA; C: suboptimal in ME and CP levels by 6%; CPh: C+PFA. Feed conversion ratio (FCR) was improved in birds fed diet A compared to diet C during the grower period (P D =0.021) and overall (P D =0.010). Phytogenic supplementation resulted in higher (P D×Ph =0.020) total tract apparent digestibility of fat in birds fed diet C compared to diet A. Birds fed diet A had higher (P D =0.001) plasma cholesterol, compared to birds fed diet C. In addition, birds fed diets A and B had higher (P D =0.002) breast protein content compared to C. Overall, PFA inclusion reduced cholesterol (P Ph =0.002) and increased plasma TAC (P Ph <0.001). Moreover, PFA increased breast (P Ph =0.001) and thigh (P Ph =0.01) TAC. In conclusion, a reduction in dietary ME and CP levels, adversely affected the FCR, whereas PFA supplementation tended (P Ph =0.089) to compensate these effects. Moreover, the addition of PFA reduced plasma cholesterol and improved plasma and meat TAC.

Effects of high selenium and fat supplementation on growth performance and thyroid hormones concentration of broilers.

A total of 400, as hatched, broilers were used to investigate the effect of increase of selenium and energy intake on thyroid hormone metabolism, growth and liver fatty acid profile. There were 5 replicates of 4 dietary treatments namely, TA (0.289mg Se per kg diet and adequate energy content), TB (0.583mg Se per kg diet and adequate energy content), TC (0.267mg Se per kg diet and 9% increase of energy content) and TD (0.576mg Se per kg diet and 9% increase of energy content). Diets were isonitrogenous. Zinc L-selenomethionine complex was used to increase Se content and corn oil was used to increase the energy content. The experiment lasted 42 days. Broiler growth performance was not significantly affected by dietary treatments. Liver glutathione peroxidase (GPx) activity increased (P<0.05) in broilers fed high Se and energy diets compared to other ones. Whole blood GPx activity was higher in Se supplemented groups however, it was reduced by age. Thyroid hormone concentrations were unaffected by dietary treatments. A significant increase of linoleic and arachidonic acid concentration (P<0.001) was observed in the liver of broilers fed diets with moderately increased energy content and supplemented with Se compared to those fed diets with moderately increased energy content alone. In conclusion, zinc L-selenomethionine complex and moderate increase of energy content did not affect growth rate or thyroid hormone metabolism but led to increased liver fatty acid content and hepatic GPx activity.

Influence of organic selenium supplementation on the accumulation of toxic and essential trace elements involved in the antioxidant system of chicken.

The aim of the study was to investigate the interactions between selenium (Se) and various trace elements, both toxic and essential, involved in the antioxidant system. A total of 128 day-old chicks (Gallus gallus, broilers) were used to investigate the effect of Se yeast supplementation on the accumulation of cadmium (Cd), copper (Cu) iron (Fe) and zinc (Zn). There were four replicates of four dietary treatments: T1 (basal diet with no added Se, analyzed to contain 0.21 mg kg(-1)), T2 (T1 with 0.15 mg kg(-1) Se added), T3 (T1 with 0.3 mg kg(-1) Se) and T4 (T1 with 3.0 mg kg(-1) Se). At week 4 and 6, two chickens per replicate pen were sacrificed for whole blood, breast muscle and liver sampling. Samples were analyzed by ICP-MS. Supplementation with Se-yeast, not only increased Se concentration but also reduced Cd concentration in the tissues. Selenium was negatively correlated with Cd and positively correlated with Zn, Cu and Fe. Cadmium was negatively correlated with Zn and Cu. Zinc was positively correlated with Cu. Iron was negatively correlated with Cu and uncorrelated with Zn and Cd. The balance between Se, Cu, Fe and Zn is important for proper antioxidant defense since they are an integral part of various antioxidant enzymes.

Effect of dietary soybean oil addition on the odd-numbered and branched-chain fatty acids in rabbit meat.

The effect of dietary soybean oil (SO) inclusion (20g/kg) on the odd-numbered (ONFA) and branched-chain (BCFA) fatty acids (FA) of two muscles, differing in fatness (Longissimus lumborum and Biceps femoris), was studied in 24 New ZealandxCalifornian rabbits. The increased muscle fatness in Biceps femoris (P<0.001) was related to higher saturated (P<0.01) and monounsaturated (P<0.01) fatty acids. Intramuscular ONFA and BCFA contents were not affected, but their proportions were reduced (P<0.01 and P<0.001) by SO addition, suggesting a dilution effect of the dietary polyunsaturates accumulated in both muscles, except for 17:0i which decreased only in Longissimus lumborum due to significant (P<0.05) soybean oilxmuscle interaction. The higher (P<0.05) BCFA contents and the FA profile in Biceps femoris were not affected by fatness, indicating an association with other muscle properties. The present study supplies new information on ONFA and BCFA in rabbit meat.

Effects of Lactobacillus acidophilus on gut microflora metabolic biomarkers in fed and fasted rats.

BACKGROUND & AIMS: Little is known about fasting effects on gut bacterial metabolism. As probiotics are purported to be beneficial for health, this study aimed to investigate the response of gut microbial metabolism on fasting with or without probiotic administration. METHODS: Sixty male adult Wistar rats were allocated to six experimental treatments, for 6 days, arranged under three nutritional schemes namely: (a) ad libitum feeding (control), (b) fasting for 3 days and re-feeding for the remainder (re-fed) and (c) fasting for 6 days combined with parenteral liquid treatment during the last 3 days (starved). Each nutritional scheme had one non-probiotic and one probiotic treatment receiving orally Lactobacillus acidophilus. Rat caecal digesta were analyzed for bacterial enzyme activities and volatile fatty acids (VFA). RESULTS: Fasted rats had significantly lower activities of alpha-galactosidase, alpha-glucosidase and beta-glucosidase and higher activities of beta-galactosidase and azoreductase compared to control and re-fed rats, irrespective of probiotic administration. Results were variable regarding cholylglycine hydrolase (CGH), while there were no differences between treatments regarding beta-glucuronidase and arylsulfatase activity. Fasted rats had significantly lower caecal VFA concentration and different fermentation patterns. L. acidophilus resulted in significantly reduced azoreductase activity and increased caecal acetate levels in fasted rats. Re-feeding appeared to restore most enzyme activities, fermentation intensity and to some extent fermentation patterns at control treatment levels. L. acidophilus resulted in significantly reduced CGH activity and increased butyrate levels in re-fed rats. CONCLUSION: The results indicate a health beneficial potential of L. acidophilus in fasted and re-fed nutritional states via reduction of harmful azoreductase and CGH activities and promotion of useful VFA components for colonic function and health.