Effect of Dietary Crude Protein Level and Supplemental Herbal Extract Blend on Selected Blood Variables in Broiler Chickens Vaccinated against Coccidiosis.

Immunoprophylaxis with a live anticoccidial vaccine is regarded as the most promising alternative in place of in-feed coccidiostats in the poultry industry. An experiment, designed as a 2 × 2 × 2 factorial arrangement with 6 replicate pens per treatment and 8 male Ross 308 chicks per pen, was conducted to evaluate the effect of dietary crude protein (CP) levels (21.6% or 23.6%, during the starter phase) and a herbal extract (HE) blend dietary supplementation (Echinacea purpurea, Salvia officinalis, Thymus vulgaris, Rosmarinus officinalis, Allium sativum, Origanum vulgare; 0 or 2 g/kg of feed) on selected hematological, biochemical, redox, and immunological parameters in broilers vaccinated against coccidiosis (anticoccidial vaccine (ACV); none or 1× dose, administered at 1 d of age). The blood samples were collected at 14 d of age. Anticoccidial vaccination (p < 0.05) had a negative effect on immune responses, as shown by a reduced total white blood cells (WBC) count, a reduced lymphocytes count (L), a higher proportion of heterophils (H) in leukogram assessments, as well as H/L-ratio increase. ACV resulted in a decrease in phagocytic activity assessed as decreased percentage of phagocytic cells, phagocytic index and NBT test, as well as in reductions in plasma glucose and LDL-cholesterol concentrations, and increases in HDL-cholesterol and aspartate aminotransferase (AST) activity. In terms of redox status, ACV significantly increased the catalase (CAT) activity and ferric reducing ability of plasma (FRAP), and decreased malondialdehyde concentrations. An increase in dietary CP in vaccinated chickens resulted in higher relative L and lower relative H counts, a lower H/L ratio, a decrease in AST and an increase in CAT activities, but also a decrease in FRAP and concentrations of lipid peroxides. Vaccinated chickens fed a diet supplemented with HE were characterized by higher relative L and lower relative H counts, a lower H/L ratio, and a decrease in AST activity. A change of diet composition, such as an increase in CP content and dietary HE supplementation, can be recommended in broilers vaccinated against coccidiosis, mainly due to its positive effect in alleviating stress levels. However, the simultaneous increase of CP and HE dietary supplementation offered no additional relevant benefits in most of the blood indices of vaccinated chickens.

Effect of copper nanoparticles on the mineral content of tissues and droppings, and growth of chickens.

We hypothesised that copper nanoparticles (NanoCu), because of their high physicochemical reactivity and bioavailability, could be used in much smaller quantities than bulk Cu, consequently reducing excretion of Cu into the environment. The objective of the study was to evaluate the effects of various levels of NanoCu on the development and growth of broiler chickens, in order to establish an optimum level of NanoCu dietary supplementation. Broiler chickens were randomly divided into five groups of 10 birds each. The control group received 7.5 mg Cu/kg feed (standard level) as CuSO4, while groups fed with complexes of NanoCu and starch received 25%, 50%, 75% and 100% of the standard level of Cu used in the control group. Chicken growth and excretion of Cu, Fe and Zn were measured during the growth period from d 7 to 42. At d 42, the slaughter characteristics, the content of Cu, Fe and Zn in the breast muscle and liver, and the oxidative status were analysed. The results indicate that using NanoCu can reduce the standard level of Cu from CuSO4 supplementation by 75% without jeopardising animal growth, and at the same time significantly decreasing Cu excretion into the environment.

The Effect of Different Levels of Cu, Zn and Mn Nanoparticles in Hen Turkey Diet on the Activity of Aminopeptidases.

The aim of the study was to estimate the influence of the different levels of Cu, Zn, and Mn nanoparticles on the activity of aminopeptidases in turkey. An experiment was carried out on 144 turkey hen Hybrid Converter. The birds were divided into groups given standard- and nanoparticle-supplementation of different level of copper (Cu 20, 10, 2 mg/kg), zinc (Zn 100, 50, 10 ppm), and manganese (Mn 100, 50, 10 ppm), covering respectively 100%, 50%, and 10% of the physiological demands for those minerals in the diet. The activity of aminopeptidases (alanyl: AlaAP, leucyl: LeuAP and arginyl: ArgAP) after supplementation of minerals was determined in the breast and thigh turkey muscle. The strongest effect of interaction among minerals supplementation form and dose on the activity levels of the aminopeptidases in thigh muscle was observed for nano-Cu already at the lowest dose of 2 mg/kg. In this dose (covering 10% of the birds' demand) nano form of supplementation significantly increased the activity of Ala-, Leu-, and ArgAP (877, 201, and 719, respectively), compared to standard form of supplementation (461, 90.5, and 576, respectively). In turn, in breast muscle, after supplementation covering 10% of the demand with the nano-Cu, nano-Zn, and nano-Mn compared to the standard form, we did not observe any significant difference in the activity levels of any of the investigated aminopeptidases, except for AlaAP under Zn supplementation. Supplementation with the 20 mg/kg of Nano-Cu (100% of demand) and with 10 mg/kg of Nano-Cu (50% of demand) inhibited the activity of all of the three aminopeptidases in thigh muscle. Supplementation of the minerals in nano form into the diet, especially of Cu and Zn in the dose covering 10% of the demand is relevant to maintain homeostasis in turkey muscles, as indicated by the activity of the aminopeptidases.

Phytase modulates ileal microbiota and enhances growth performance of the broiler chickens.

Phytase is well studied and explored, however, little is known about its effects on the microbial ecology of the gastrointestinal tract. In total, 400 one-day-old female Ross 308 chicks were randomly distributed to four experimental groups. The dietary treatments were arranged as a 2 × 2 complete factorial design, with the factors being adequate (PC) or insufficient calcium (Ca) and digestible phosphor (dP)(NC) and with or without 5000 phytase units (FTU)/kg of Escherichia coli 6-phytase. The gastrointestinal tract pH values, ileal microbial communities and short-chain fatty acid concentrations in the digesta were determined. The reduction in Ca and dP concentration significantly affected pH in the crop and caeca, and addition of phytase to the NC resulted in a pH increase in the ileum. The reduction in Ca and dP concentration significantly lowered, while phytase supplementation increased ileal total bacterial counts. Additionally, the deficient diet reduced butyrate- but increased lactate-producing bacteria. The addition of phytase increased Lactobacillus sp./Enterococcus sp. whereas in case of Clostridium leptum subgroup, Clostridium coccoides-Eubacterium rectale cluster, Bifidobacterium sp. and Streptococcus/Lactococcus counts, a significant Ca and dP level x phytase interaction was found. However, the recorded interactions indicated that the effects of phytase and Ca and dP levels were not consistent. Furthermore, the reduction of Ca and dP level lowered Clostridium perfringens and Enterobacteriaceae counts. The analysis of fermentation products showed that reducing the Ca and dP content in the diet reduced total SCFA, DL-lactate, and acetic acid in the ileum whereas phytase increased concentrations of these acids in the NC group. This suggests that P is a factor which limits fermentation in the ileum. It may be concluded that phytase plays a role in modulating the gut microbiota of chicken, however, this is clearly linked with the levels of P and Ca in a diet.

Dietary nisin modulates the gastrointestinal microbial ecology and enhances growth performance of the broiler chickens.

Due to antimicrobial properties, nisin is one of the most commonly used and investigated bacteriocins for food preservation. Surprisingly, nisin has had limited use in animal feed as well as there are only few reports on its influence on microbial ecology of the gastrointestinal tract (GIT). The present study therefore aimed at investigating effects of dietary nisin on broiler chicken GIT microbial ecology and performance in comparison to salinomycin, the widely used ionophore coccidiostat. In total, 720 one-day-old male Ross 308 chicks were randomly distributed to six experimental groups. The positive control (PC) diet was supplemented with salinomycin (60 mg/kg). The nisin (NI) diets were supplemented with increasing levels (100, 300, 900 and 2700 IU nisin/g, respectively) of the bacteriocin. The negative control (NC) diet contained no additives. At slaughter (35 days of age), activity of specific bacterial enzymes (α- and ß-glucosidases, α-galactosidases and ß-glucuronidase) in crop, ileum and caeca were significantly higher (P<0.05) in the NC group, and nisin supplementation decreased the enzyme activities to levels observed for the PC group. A similar inhibitory influence on bacterial activity was reflected in the levels of short-chain fatty acids (SCFA) and putrefactive SCFA (PSCFA) in digesta from crop and ileum; no effect was observed in caeca. Counts of Bacteroides and Enterobacteriacae in ileum digesta were significantly (P<0.001) decreased by nisin and salinomycin, but no effects were observed on the counts of Clostridium perfringens, Lactobacillus/Enterococcus and total bacteria. Like salinomycin, nisin supplementation improved broiler growth performance in a dose-dependent manner; compared to the NC group, the body weight gain of the NI900 and NI2700 groups was improved by 4.7 and 8.7%, respectively. Our findings suggest that dietary nisin exerts a mode of action similar to salinomycin and could be considered as a dietary supplement for broiler chickens.