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Pirgozliev V.,Avian Science Research Center | Pirgozliev V.,Harper Adams University College | Bedford M.R.,AB Vista Feed Ingredients
British Journal of Nutrition | Year: 2013

A total of 364 female Ross 308 chicks (1 d old) were used in the present study conducted in floor pens to investigate the effects of graded levels of supplementary bacterial phytase on dietary energy utilisation and growth performance. For this purpose, four maize-soyabean-based diets were offered to the birds from 0 to 21Â d of age. These included a suboptimal P negative control (NC, 3·0Â g/kg non-phytate P), NC+250 phytase units (FTU)/kg feed, NC+500Â FTU and NC+2500Â FTU. The effect of phytase activity on bird growth performance was best described as a linear relationship between increasing dose and increased feed intake (P<Â 0·001), but was quadratic for body-weight gain (P=Â 0·002) and feed efficiency (P=Â 0·023). There was no significant response (P>0·05) of dietary apparent metabolisable energy (AME) to supplementary phytase. The birds fed phytase increased their retention of total carcass energy in a linear fashion (P=Â 0·009) with increased phytase dose. The efficiency of dietary AME used for overall carcass energy retention also improved (P=Â 0·007) in a linear manner with increased dietary phytase activity. Dietary net energy for production (NEp) increased (P=Â 0·047) with an increase in phytase dose following a linear pattern, as an increase of 100Â FTU increased dietary net energy by 15·4Â J (estimated within the range of doses used in the present experiment). Dietary NEp was more highly correlated with performance criteria than dietary AME, and it seems to be a more sensitive way to evaluate broiler response to phytase supplementation. Copyright © The Authors 2012. Source

Pirgozliev V.,Avian Science Research Center | Bedford M.R.,Vista Feed Ingredients | Acamovic T.,Vista Feed Ingredients | Mares P.,Vista Feed Ingredients | Allymehr M.,Vista Feed Ingredients
British Poultry Science | Year: 2011

1. Four diets were offered to broiler chickens from 7 to 17d of age; these included a phosphorus-adequate positive control (PC) (4 7g/kg available P), a sub-optimal P negative control (NC, 2 5g/kg available P) with (500 and 12500FTU/kg) and without phytase. Dietary apparent metabolisable energy (AME), dietary net energy for production (NEp), the efficiency of AME retention (Kre), heat production and total tract amino acid digestibility coefficients were determined. The determination of NEp involved a comparative slaughter technique in which growing chickens were fed the experimental diets ad libitum. 2. Feed intake, weight gain and feed conversion efficiency increased significantly in a dose dependent manner in response to dietary phytase activity. Overall, the NEp of the phytase supplemented diets significantly improved by approximately 15 6% compared with the negative control, while dietary AME was unaffected. Although phytase did not affect AME, the large increase in the NEp demonstrated that dietary phytases improves energy utilisation, i.e. diverting more energy, not accounted for in the AME procedure, for production. This is largely a result of the stimulatory effect that phytase has on feed intake rather than on digestibility of the diet. 3. Overall, the diet supplemented with 12500FTU had 6 4% significant improvement in total tract digestibility coefficients of the total amino acids compared with the negative control. With regard to individual amino acids, the impact of phytase was far more pronounced for threonine, an important component of the gastrointestinal mucin, than for other amino acids. 4. Dietary NEp was more highly correlated with performance criteria than dietary AME and seems to be a more sensitive way to evaluate broiler response to phytase supplementation. © 2011 British Poultry Science Ltd. Source

Sparks N.H.C.,Avian Science Research Center
Avian Biology Research | Year: 2011

The earliest avian eggshells probably lacked pigmentation but, in part to help protect the eggs from predators, many species of bird have evolved a diverse range of coloured shell markings. However, the wide variation in shell colour and pigment pattern arise out of probably no more than three molecules, protoporphyrin, biliverdin and zinc biliverdin chelate. These molecules are constructed from four pyrrole rings (tetrapyrroles) but, while their synthesis pathways are well defined, the site(s) of shell pigment synthesis is less well defined. It is probable that biliverdin is synthesised in the uterus. While there is evidence that protoporphyrin is also synthesised in the uterus the evidence for this is more circumstantial. What is known is that pigment is secreted from the surface epithelial cells of the uterus into the uterine fluid and hence onto the shell. It is notable that the protoporphyrin content the uterine tissue of white-egg laying birds is not dissimilar to that of brown-egg laying birds, the control mechanisms being exerted at the level of protoporphyrin release from the surface epithelial cells into the lumen of the uterus. Similarly white-shelled eggs are not necessarily devoid of pigment. While pigment is normally concentrated on the outer surface of the shell there are many species of bird that incorporate pigment into the outer half or third of the shell. This has stimulated research into potential functional roles for shell pigments, including substituting for calcium carbonate when calcium is limiting and improving shell strength through 'lubricating' the calcite crystals. Source

Bravo D.,Pancosma S. A. | Pirgozliev V.,Avian Science Research Center | Pirgozliev V.,National United University | Rose S.P.,National United University
Journal of Animal Science | Year: 2014

A total of 210, 1-d-old Ross 308 male broiler chickens were used in an experiment to investigate the effects of a supplementary mixture containing 5% carvacrol, 3% cinnamaldehyde, and 2% capsicum on dietary energy utilization and growth performance. The 2 diets were offered ad libitum to the chickens from 0 to 21 d of age. These included a maizebased control diet and the control diet with 100 g/t of supplementary plant extracts. Dietary apparent ME, N retention (NR), and fat digestibility (FD) coefficients were determined in the follow-up metabolism study between 21 and 24 d of age. Feeding the mixture of carvacrol, cinnamaldehyde, and capsicum increased weight gain by 14.5% (P = 0.009), improved feed efficiency by 9.8% (P = 0.055), and tended to increase (P = 0.062) carcass energy retention and reduce (P = 0.062) total heat loss compared with feeding the control diet. There was a 16.1% increase (P = 0.015) in carcass protein retention but no difference in carcass fat retention. Feeding plant extracts improved dietary FD by 2.1% (P = 0.013) but did not influence dietary NR. Supplementation of plant extract resulted in a 12.5% increase (P = 0.021) in dietary NE for production (NEp), while no changes in dietary ME were observed. The experiment showed that although dietary essential oils did not affect dietary ME, they caused an improvement in the utilization of energy for growth. Plant extracts may affect metabolic utilization of absorbed nutrients. Studies that have focused solely on the effect of plant extracts on ME alone may well have not detected their full nutritional value. © 2014 American Society of Animal Science. All rights reserved. Source

Dixon L.M.,Animal and Veterinary science Research Group | Sparks N.H.C.,Avian Science Research Center | Rutherford K.M.D.,Animal and Veterinary science Research Group
Poultry Science | Year: 2016

Early life experiences can be important in determining offspring phenotypes and may influence interaction with the environment and hence health, welfare, and productivity. The prenatal environment of poultry can be divided into the pre-lay environment and the egg storage/incubation environment, both of which can affect offspring outcomes. The ability to separate maternal and egg/incubation effects makes birds well suited to this type of research. There are many factors, including feeding and nutrition, environmental conditions, husbandry practices, housing system, social environment, infectious environment, and maternal health status, that can influence both the health and performance and behavior and cognition of the offspring. There are some aspects of the environments that can be changed to produce beneficial effects in the offspring, like addition of certain additives to feed or short changes in incubation temperatures, while other aspects should be avoided to reduce negative effects, such as unpredictable feeding and lighting regimens. Measures of offspring characteristics may prove to be a useful method of assessing parent stock welfare if known stressors result in predictable offspring outcomes. This has the advantage of assessing the parent environment without interfering with the animals and possibly affecting their responses and could lead to improved welfare for the animals. © 2016 The Author 2015. Published by Oxford University Press on behalf of Poultry Science Association. Source

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