The effects of a short-term molt method using cassava meal, broken rice, or corn on ovarian regression, bone integrity, and postmolt egg production and quality in older (95 week) laying hens

Abstract

This study was conducted to determine the ability of different molt diets to induce molt in 95-wk-old hens. The hens were randomly assigned to 4 treatments of 60 birds each: 1) molted by full feeding with broken rice (BROK), 2) corn (CRN), 3) cassava (CASS), or 4) nonmolted control (CONT) for 14 d. At 15 d, all hens were fed a layer diet (17% CP), and production performance was measured for 20 wk. Feed intake was depressed (P < 0.05) in the CASS treatment compared with BROK and CRN treatments during the 14 d. The most significant BW loss occurred in the CASS treatment (21.9%), whereas BROK and CRN treatments were 7.6 and 9.3%, respectively. The CASS treatment resulted in total cessation of egg production within 7 d, whereas those of BROK and CRN treatments decreased to 3.7 and 8.7%, respectively. Ovary weights, oviduct weights, and oviduct lengths of the CASS treatment were not significantly different from those of BROK and CRN treatments (P > 0.05). The weight of spleen and thymus glands, blood heterophil:lymphocyte ratios, bone parameters, and mortality during the 14-d treatment were not affected by treatments. No significant differences were found among treatments for postmolt cumulative egg production, egg weight, feed intake, and mortality. Significant (P < 0.05) improvements in albumen quality were observed in the CASS treatment, although shell thickness of this treatment was reduced (P < 0.05) compared with the CONT treatment in wk 2 after the 14-d treatment. With respect to shell ultrastructural traits, the palisade layer of CASS eggs was shorter (P < 0.05) than that of CONT eggs determined in wk 2 after the 14-d treatment. In addition, evidence of abnormal mammillae was detected in an egg produced by the CASS hens. This research indicates that cassava diets can induce molt in hens. Nonetheless, the technique needs to be adjusted to improve postmolt egg production and shell quality.