Mohiti-Asli, M., Shariatmadari, F., Lotfollahian, H. and Mazuji, M. T. 2008. Effects of supplementing layer hen diets with selenium and vitamin E on egg quality, lipid oxidation and fatty acid composition during storage. Can. J. Anim. Sci. 88: 475Á 483. A 7-wk trial was carried out to investigate the effect of vitamin E and inorganic and organic selenium added to hens' diet on quality and lipid stability of eggs during storage. One hundred forty-four Hy-Line W-36 hens (63-wk of age) were divided into six equal groups. Five groups received a basal diet supplemented with 0.4 mg kg(1 sodium selenite or selenium yeast, 200 mg kg (1 vitamin E or a combination of selenium and vitamin E; whereas the control group received no supplementation. Hen production was assessed daily and fresh egg quality parameters were determined every 2 wk. Eggs were stored under different conditions (48C, 23Á278C or 318C) for 14 d. Eggs were analyzed for quality characteristics, egg component weight, Malondialdehyde values as a secondary oxidation product and yolk fatty acid (FA) composition. The performance of the hens and egg weights were not affected either by the source of the selenium or by the vitamin E. The inclusion of selenium or vitamin E in the diet significantly increased their concentrations in the egg. The supplemented diets also improved egg quality, oxidative stability and fatty acid composition during storage.Key words: Vitamin E, selenium, lipid peroxidation, egg fatty acid composition, storage Mohiti-Asli, M., Shariatmadari, F., Lotfollahian, H. et Mazuji, M. T. 2008. Incidence du se´le´nium et de la vitamine E dans la ration des pondeuses sur la qualite´des aeufs, l'oxydation des lipides et la composition en acides gras durant l'entreposage. Can. J. Anim. Sci. 88: 475Á483. Un essai de sept semaines devait pre´ciser les effets de la vitamine E ainsi que du se´le´nium mine´ral ou organique, ajoute´s à la ration des pondeuses, sur la qualite´des aeufs et la stabilite´des lipides pendant l'entreposage. Cent quarante-quatre poules W-36 Hy-Line (de 63 semaines) ont e´te´re´parties en six groupes e´gaux. Cinq groupes ont rec¸u la ration de base enrichie de 0,4 mg de se´le´nite de sodium ou de se´le´nium de levure par kg, ou 200 mg de vitamine E ou de se´le´nium et de vitamine E par kg, tandis que le groupe te´moin n'a rec¸u aucun supple´ment. La ponte a e´teé´v alue´e quotidiennement et les parame`tres qualitatifs des aeufs frais ont e´te´de´termine´s une semaine sur deux. Les aeufs ont e´te´garde´s 14 jours dans des conditions varie´es (4 8C, 23Á27 8C ou 31 8C). On a ensuite analyse´leur qualite´, le poids de chaque composante, la concentration de malondialdehyde en tant que produit secondaire de l'oxydation et la composition du jaune en acides gras. Le rendement des pondeuses et le poids de l'aeuf ne sont pas affecte´s par la source de se´le´nium ni la vitamine E. L'enrichissement de la ration avec du se´le´nium ou de la vitamine E augmente sensiblement la concentration de ces substances dans l'aeuf. Les supple´ments ame´lior...

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The aim of this study was to evaluate the effects of thermal manipulation (TM) during pre and post-hatch periods on thermotolerance of male broiler chickens exposed to chronic heat stress (CHS) during the finisher phase (34 ± 2°C, 6 h/day). Seven hundred fertile eggs of Ross 308 were assigned to the following groups: 1) control group incubated and housed in standard conditions, 2) pre-hatch treatment (PRE), the eggs were exposed to 39.5°C and 65% RH for 12 h, d from embryonic d 7 to 16 and after hatching the chicks where housed in standard conditions; 3 and 4) post-hatch TM at d 3 (PO3) and post-hatch TM at d 5 (PO5), which had the same incubation conditions as control and exposed to 36 to 38°C for 24 h at 3 and 5 days of age, respectively. TM in PRE group resulted in delay in the hatch time (6 h) along with reduction in body weight compared to control (P = 0.02). TM caused a significant reduction of facial surface temperature (FST) until d 28 (P < 0.02), but not significant during CHS. Body weight gain was suppressed in PO3 and PO5 groups at d 14 (P = 0.007) and compensated at d 28. However, TM led to higher BWG (P = 0.000) but lower FCR (P = 0.03) and mortality at the first week of CHS compared to control. European production efficiency index was higher in TM-treated chickens compared to control (P = 0.01). TM reduced the blood concentration of uric acid, total protein, T3, and T4 in which thyroid hormones in PO3 and PO5 treatments showed more reduction rather than other groups. In PRE group, chickens had lower abdominal fat pad than control (P = 0.0001). The relative weight of heart was decreased in TM groups (P = 0.001). It was concluded that TM may induce thermotolerance in growing broilers, possibly through the modification of physiological parameters of broilers especially during the first week of CHS.

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