To evaluate the effects of whey protein (WP) sources on performance, liver antioxidants and immune responses of broiler chickens, 300 one‐d‐old male Ross 308 chickens were randomly allocated into six treatments with five replications of 10 birds each. This study was conducted on the basis of a completely randomized design in a 3 × 2 factorial arrangement with dietary supplemental WP sources (no WP; 2% WP and 2% whey protein concentrate (WPC)) and ethanol (zero and 6%) into drinking water. Birds were challenged with ethanol 6% from 10 to 24 days of age. Growth performance, immune responses, intestinal morphology and antioxidant enzymes were assessed in both challenged and non‐challenged groups. There was a significant interaction between ethanol and WP sources for growth performance, so that weight gain (WG), feed intake (FI) and feed conversion ratio (FCR) were significantly improved in broiler chickens challenged with ethanol and fed with WP (p < .05). Intestinal morphology, humoral responses and heterophil to lymphocyte ratio (H/L) were not affected by WP sources. Cellular immunity responses were significantly lower in control group and challenged birds fed with WP compared with other groups after 48 hr of phytohemagglutinin‐P (PHA‐P) injection. Ethanol challenge decreased liver antioxidant enzyme activities and increased levels of malondialdehyde (MDA) and alanine aminotransferase (ALT) activities. Dietary inclusion of WP and WPC increased levels of liver antioxidant enzymes and decreased MDA and ALT activities. It can be recommended to use WP for improving the growth performance and liver antioxidant enzymes in broiler chickens challenged with ethanol.

A study was conducted to isolate lactobacilli from the gastrointestinal (GI) tract of broiler chickens and to evaluate their application as a probiotic supplement. The GI contents of 12 broiler chickens from three different ages were collected and cultured on Man Rogosa and Sharp (MRS) agar. In order to determine bacterial species, different grown colonies were separated and subjected to the sequencing of the 16s ribosomal DNA fragment. An auto-aggregation test was performed for 39 isolated lactobacilli bacteria. Eight species were selected because of their convenient aggregation. In vitro tests including antibacterial activity, resistance to low pH, resistance to bile extract, ability to produce H 2 O 2 , cell surface hydrophobicity and adhesion activities on crop epithelial cells were performed for evaluating of probiotic potential for each strain. These tests were ranked according to their priority for probiotic strains. The total score obtained from different experiments is indicator of suitable strain. Under the in vitro conditions and with respects to the probiotic traits, Lactobacillus salivarius caeca4 and Lactobacillus crispatus caeca10 were suggested as probiotic strain, and can be evaluated in an in vivo conditions of commercial birds.

Probiotics are beneficial microorganisms and have long been used in food production as well as health promotion products. Bioengineered probiotics are used to express and transfer native or recombinant molecules to the mucosal surface of the digestive tract to improve feed efficiency and promote health. Lactococcus lactis is a potential probiotic candidate to produce useful biological proteins. The aim of this investigation was to develop a recombinant Lactococcus lactis with the potential of producing phytase. To enhance the efficiency of expression and secretion of recombinant phytase, usp45 signal peptide was added to the expression vector containing phytase gene (appA2) derived from Escherichia coli. Sequencing of recombinant plasmid containing appA2 showed the correct construction of plasmid. Total length of the phytase insert was 1.25 kbp. A Blast search of the cloned fragment showed 99% similarity to the reported E. coli phytase sequence in the GenBank (accession number: AM946981.2). A plasmid containing usp45 and appA2 electrotransferred into Lactococcus lactis. Zymogram with polyacrylamide gel revealed that the protein extract from the supernatant and the cell pellet of recombinant bacteria had phytase activity. Enzyme activity of 4 U/ml was obtained in cell extracts, and supernatant maximal phytase activity was 19 U/ml. The recombinant L. lactis was supplemented in broiler chicken feed and showed the increase of apparent digestibility on phytate phosphorus in the digestive tract and it was same as performance of E. coli commercial phytase.

Background: This study intended to assess individual and combined adsorption potentials of

The availability of plant phosphorus in the gut chicken can be improved by increasing phosphorus retention using phytase enzyme or a probiotic with phytase activity as an alternative. In this study, the efficacy of a recombinant probiotic, Lactococcus lactis (L. lactis), with a potential of phytase production was evaluated in broiler chickens. To this aim, 360 one-day-old male broiler Cobb 500 were divided into six treatments with six replicates and reared to 42 days of age. The experimental treatments included positive control diet containing adequate phosphorus (PC), negative control diet containing reduced available phosphorus (NC), negative control diet involving recombinant L. lactis (RLL), negative control diet containing both recombinant L. lactis and Lactobacillus salivarius (RLL + LBS), negative control diet including nonrecombinant L. lactis (LL) and negative control diet containing Hostazym ® . Growth performance, total tract apparent disappearance of phytate-P and nutrient retention, mineral content of the tibia and histomorphology of jejunum were evaluated at the age of 35 days. Based on the results, the phosphorus (P) deficiency in the diet reduced body weight (BW), average daily gain (ADG), length and strength of tibia and increased feed conversion ratio (FCR) compared to PC group. However, the supplementation of Hostazym ® or RLL probiotic into the feed improved BW, ADG, FCR, disappearance of Phytate-P and retention of P, length and strength of the tibia in a level similar to PC treatment. Phosphorus content of tibia in the chickens fed P-deficient diets containing RLL was similar to that of the tibia in the control group. Excreta phytate and total P excretion of the chickens decreased when diets contained Hostazym ® , RLL and RLL + LBS. In addition, the diet containing RLL + LBS probiotic increased villi height compared with other treatments (p < .05). Further, recombinant L. lactis could represent phytase activity in the gut environment of the chickens and could be an alternative to the commercial phytase. K E Y W O R D S broiler chicken, Lactococcus lactis, phosphorus, phytase, probiotic How to cite this article: Mohammadi Ziarat M, Kermanshahi H, Nasiri Mogaddam H, Majidzadeh Heravi R. Performance of an Escherichia coli phytase expressed in Lactococcus lactis on nutrient retention, bone traits and intestinal morphology in broiler chickens.

This study was conducted to investigate the efficacy of in ovo administration of aluminium hydroxide (AH) and/or mannan oligosaccharide (MOS) adjuvants along with lentogenic VG/GA strain-Avinew to alleviate the embryonic pathogenicity of Newcastle disease virus. Six hundred and thirty fertilized Bovans eggs were divided into nine groups of 70 each incubated in a commercial hatchery and administered with eight types of in ovo injections in a factorial design of 2 × 2 × 2 including with/without AH, MOS and Newcastle disease vaccine (NDV), and one uninjected group on day 18 of incubation. Hatchability was higher in the eggs received MOS and/or AH adjuvants plus NDV compared those injected with NDV alone which confirmed the attenuation of NDV. However, the average daily feed intake and feed conversion ratio of pullets hatched from NDV-injected eggs were significantly reduced, but did not affect growth performance during 0-42 days of age. The performance of pullets hatched from eggs injected with AH, MOS or their mixture with NDV was not significantly different during all growth periods. Pullets from MOS + vaccine injected eggs had significantly higher antibody titres against NDV compared to those hatched from either injected with saline or uninjected on d 28 (p < .05). In addition, AH plus vaccine and MOS significantly improved total anti-SRBC and IgG respectively. Histological observation revealed that injection of MOS adjuvant into eggs led to increase crypt depth, whereas AH injection caused a reduction in villus surface area of jejunum in chicks on d 14 post-hatch. It is concluded that in ovo MOS injection as compared to AH may be more effective to attenuate the embryonic pathogenicity of in ovo NDV injection.

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