Browsing by Author "Acamovic, T."

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The Effect on Performance, Energy Metabolism and Hepatic Carotenoid Content When Phytase Supplemented Diets Were Fed To Broiler Chickens
(Elsevier Sci Ltd, 2010) Pirgozliev, V.; Karadas, F.; Pappas, A.; Acamovic, T.; Bedford, M. R.
Two basal diets containing an adequate and a low supply of available P (4.7 vs 2.5 g/kg diet) and three others containing a low available P but supplemented with 250, 500 and 12,500 units of phytase (FTU) per kg diet, respectively, were prepared. Each diet was fed ad libitum to birds in six metabolism cages (five birds in each cage) in a randomised block design. It was found that birds fed a high (12,500 ETU) dosage of phytase grew faster (P < 0.001) and retained proportionally more carotenoids in the liver (P < 0.05) compared to birds fed unsupplemented diet. The results suggest that dietary phytase may improve the anti-oxidative status of birds fed low P diets through enhancing dietary carotenoid availability. (C) 2010 Elsevier Ltd. All rights reserved.
Effects of Carotenoids From Lucerne, Marigold and Tomato on Egg Yolk Pigmentation and Carotenoid Composition
(Taylor & Francis Ltd, 2006) Karadas, F.; Grammenidis, E.; Surai, P. F.; Acamovic, T.; Sparks, C.
1. The effects of various sources of natural carotenoids (Px alfalfa concentrate, tomato powder and marigold extract) as feed additives in quail diets on egg yolk pigmentation and carotenoid composition were investigated. 2. Adult Japanese quail were fed one of 5 different diets for 23 d: three diets each contained Px alfalfa concentrate (PX) or tomato powder (TP) or marigold extract (MG), one diet contained marigold extract and tomato powder (MG+TP) and a control diet (wheat/barley based) was low in carotenoid. All products were added at a rate of 2%, apart from marigold extract which was added at a rate of 0(.)2%. 3. Visual assessment of yolk colour (Roche colour fan) showed a stabilised yolk colour of 1(.)6, 7(.)7, 8(.)5, 8(.)8 and 10(.)6 for the control, PX, TP, MG and MG+TP treatments, respectively. 4. The total carotenoid concentration of the egg yolks were 2(.)2, 22(.)4, 4(.)1, 39(.)0 and 37(.)7 mg/g for the experimental groups fed the following diets: control, PX, TP, MG and MG+TP, respectively. Deposition of retinol, alpha-tocopherol and gamma-tocopherol in the egg yolk was unaffected by treatments. 5. Lutein was shown to be the major carotenoid in the egg yolk, comprising 1(.)65, 17(.)97, 2(.)03, 31(.)14 and 28.57 mg/g in control, PX, TP, MG and MG+TP, respectively. Inclusion of TP in the quail diet resulted in lycopene transfer to the egg. 6. It was concluded that, in comparison with the control group, there was an increase in the yolk concentrations of lutein, zeaxanthin, lycopene and beta-carotene in eggs produced by female quail fed diets supplemented with natural carotenoids.
Effects of Different Dietary Phytase Activities on the Concentration of Antioxidants in the Liver of Growing Broilers
(Wiley, 2010) Karadas, F.; Pirgozliev, V.; Pappas, A. C.; Acamovic, T.; Bedford, M. R.
P>One-hundred and fifty male chickens were used to evaluate the effects of different activities (0, 250, 500, 12 500 FTU/kg) of phytase on their performance and antioxidant concentration in the liver. The chicks were housed in 30 cages and were allocated to six replicates of five dietary treatments. All diets were formulated to be adequate in energy and protein (12.90 MJ/kg metabolizable energy, 214 g/kg crude protein), however, the negative control (NC) was lower in available P compared with the positive control (PC) (2.5 vs. 4.5 g/kg diet). The other three diets were the NC supplemented with phytase at 250, 500 and 12 500 FTU/kg (NC + 250, NC + 500 and NC + 12 500 FTU respectively). The concentration of antioxidants in the liver of the birds was determined using HPLC at 21 days of age. Low P diets (NC) reduced weight gain, however, supplementation with phytase improved weight gain to the extent that it was better than the PC at the 12 500 FTU treatment (p < 0.05). Feed conversion ratio was also improved by the high level of phytase supplement more than other treatments (p < 0.05). Feed consumption was not affected either by dietary phosphorus concentration or by different phytase supplementation. The antioxidant data showed that the unsupplemented diet with low phosphorus (NC) decreased the concentration of coenzyme Q(10) and retinol-linoleate in the liver compared with that of birds on the adequate phosphorus treatment (PC). Phytase supplementation, especially at the higher doses (500 and 12 500 FTU) increased the level of coenzyme Q(10) to the same level as the PC treatment. In addition, the highest dose (12 500 FTU) of phytase increased retinol concentration in the liver of chickens compared with those on the NC treatment. The highest inclusion level of phytase increased the alpha-tocopherol level in the liver compared with the lower levels of phytase (NC + 250 and NC + 500 FTU).