A total of 392 twenty eight week-old laying hens was used to study the effects of dietary inclusion of solvent-extracted palm kernel cake (PKC) (0%, 12.5% and 25%) and enzyme (mixture of mannanase, α-galactosidase and protease) supplementation (0 kg/t, 1 kg/t and 2 kg/t) on the performance of laying hens. The levels of PKC did not significantly influence nitrogen corrected true metabolizable energy (TME n ) of the diets. Enzyme-supplemented PKC had significantly higher AME and TME n values than PKC diets with no enzyme supplementation. Dietary inclusion of 12.5% and 25% PKC in the diets of laying hens did not adversely affect mean egg production or daily egg mass. However, layers consumed significantly more PKC-based diets and had significantly poorer feed conversion ratios (FCR) than controls. However, the feed intake and FCR of hens provided the 12.5% PKC-based diets with enzyme supplementation at 1 kg/t did not differ from the controls. Dietary inclusion of PKC or enzyme did not affect eggshell quality, but egg yolk colour was significantly paler when layers were fed the 25% PKC diet.

Stress and fear responses were evaluated in broiler chicks that were pretreated for 24 h with 0 ppm (control) or 1,200 ppm of L-ascorbic acid (AA) in their drinking water. The birds were subsequently subjected to either upright handling (UH) or inverted (IH) handling for about 45 s. Heterophil (H) counts, lymphocyte (L) counts, and H/L ratios (H/L) ratios were determined immediately (T0) and at 20 h (T20) following the handling treatment. The H/L ratios were similar for both groups at T0, whereas 20 h after the handling treatment, AA-supplemented birds had lower ratios than controls, resulting in a significant water treatment x time of blood sampling interaction. Inverted handling had negligible effect on H/L ratios but augmented tonic immobility (TI) durations as compared with UH. Irrespective of handling procedure, supplemental AA reduced underlying fearfulness, as measured by TI reaction. Neither water treatment nor handling method had significant effect on number of attempts to induce TI.

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