The effects of housing environment on liver health of laying hens

Authors: JIANG, S - Southwest University; HESTER, P - Purdue University; HU, J - Purdue University; YAN, F - Purdue University; Dennis, Rachel; Cheng, Heng Wei

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2014
Publication Date: 5/7/2014
Publication URL: https://handle.nal.usda.gov/10113/59751
Citation: Jiang, S., Hester, P.Y., Hu, J.Y., Yan, F.F., Dennis, R.L., Cheng, H. 2014. The effects of housing environment on liver health of laying hens. Poultry Science. 93:1618-1622.

Interpretive Summary: Fatty liver is a common energy metabolic disorder in animals. Chicken are a high risk species for developing fatty liver. Fatty liver causes a significant drop in egg production and frequently leads to sudden death in hens. This study examined the effects of type of housing, including access to perches, on fat deposition and liver health in laying hens. In Experiment 1, 144 18-wk-old Bovans Brown hens were assigned randomly to 12 conventional cages with 2 hens per cage and 12 littered floor pens with 10 hens per pen. Half of the floor pens had a perch, while the other half did not have a perch. In Experiment 2, 324 17-wk-old White Leghorn hens were housed in 1 of 4 treatments with 9 hens per cage. Treatment 1 hens never had access to perches during their life cycle. Treatment 2 hens had access to perches during the pullet phase only. Treatment 3 hens had access to perches during the laying phase only. Treatment 4 hens always had access to perches. The results indicated that caged hens were more susceptible to fatty liver disorder than hens housed in pens. Providing perches to stimulate hens' activity in both floor pens as well as cages were ineffective in reducing fat deposition in the liver. These data may be used by egg producers to develop housing environments for improving chicken welfare.

Technical Abstract: Fatty liver is a common energy metabolic disorder in caged hens. Considering that the egg industry is shifting from conventional cages to alternative housing systems such as enriched cages, the objective of this study was to determine the effects of type of housing, including access to perches, on fat deposition and liver health in laying hens. In Experiment 1, 144 18-wk-old Bovans Brown hens were assigned randomly to 12 conventional cages with 2 hens per cage and 12 littered floor pens with 10 hens per pen. Half of the floor pens had a perch, while the other half did not have a perch. In Experiment 2, 324 17-wk-old White Leghorn hens were housed in 1 of 4 treatments with 9 hens per cage. Treatment 1 hens never had access to perches during their life cycle. Treatment 2 hens had access to perches during the pullet phase only. Treatment 3 hens had access to perches during the laying phase only. Treatment 4 hens always had access to perches. Liver weight, abdominal fat pad weight, BW, liver fat, and circulating alanine transaminase, aspartate transaminase, and serum adiponectin (Experiment 2 only) were determined. In Experiment 1, caged hens had higher % liver fat and alanine transaminase activity than hens housed in floor pens, but no differences in liver function related parameters were found in hens from floor pens with and without perches. In Experiment 2, caged pullet and laying hens with access to perches had no effect on parameters related to liver health in 71-wk-old hens. However, perch access during the egg laying phase reduced relative abdominal fat pad weights as compared to hens without perches. These results suggest that caged hens may be more susceptible to fatty liver disorder than hens housed in pens. Providing perches as a means of stimulating activity in both floor pens as well as cages were ineffective in reducing fat deposition in the liver and altering enzyme activities related to improved liver function