Effects of Water Deprivation during the Prelaying Period on Eggshell Quality, Wet Droppings and Blood Physiology in Laying Hens

Abstract

The influence of water deprivation at the onset of lay on subsequent eggshell quality, fecal moisture content and blood physiology was investigated in ISA Brown pullets. Kidney and bone appearances were also determined at the end of the study. The pullets were randomly divided into 3 groups; control, dehydrated, and dehydrated+NH₄Cl groups. The birds in the control group were provided a layer diet with water at all times. At 20 weeks of age, drinking water supply in the dehydrated and dehydrated+NH₄Cl groups was removed completely for 48 hours whereas feed was available at all times. Thereafter, the water was provided until the end of the trial. The birds in the dehydrated+NH₄Cl group were fed on the control diet added with ammonium chloride (NH₄Cl) at a level of 1% throughout the rehydration phase. Water deprivation for 2 days at the onset of lay did not affect eggshell quality throughout the experimental period. An incidence of poor eggshell was observed in the dehydrated+NH₄Cl group as evidenced by reduced shell weight and shell thickness at 24 weeks of age (P<0.05). During the 2 days of dehydration, fecal moisture contents were significantly reduced for the birds in the two groups of dehydration. However, the excreta moisture of the birds in these groups increased rapidly as the drinking water was returned and significantly greater than that of the control birds by 6 hours of water replenishment. On Week 8 of rehydration, the increase of the manure moisture was observed again for the dehydrated+NH₄Cl hens when compared with the control birds (P<0.05). Interruption of available drinking water increased hematocrit values for the two groups of dehydration during 48 hours of water deprival. Hematocrit values of the hens in these groups, however, were rapidly decreased as the water was reintroduced and significantly reduced on Week 8 of rehydration for the dehydrated hens fed with the acidified diet. Water deprivation was associated with increases in the concentration of sodium in plasma whereas plasma pH was inconsistent and varied among the experimental groups. Decreased humerus weight was observed in the dehydrated+NH₄Cl hens necropsied at the end of the study.