Rearing cage type and dietary limestone particle size: I, effects on growth, apparent retention of calcium, and long bones attributes in Lohmann selected Leghorn-Lite pullets

Abstract

Effects of rearing cage type and dietary limestone particle size ( LPS ) on growth, apparent retention ( AR ) of nutrients, and bone quality were investigated. The treatments were arranged in a 2 × 3 factorial with cage (conventional, CON and furnished, FUR ) and LPS (fine, < 0.595 mm, F ; medium, 0.595 to < 1.68 mm, M ; and 1:1 mixture of F and M wt/wt; FM ). A total of 900-day-old Lohmann LSL-Lite chicks were placed in CON (20 chicks/cage) and FUR (30 chicks/cage) based on BW. The diets were formulated according to breeder's nutrient specifications for starter, grower, and developer phases. At the end of 4, 12, and 16 wk of age ( woa ), 2 pullets/cage were euthanized for samples. At 12 and 16 woa, 1 pullet/cage was transferred to metabolism cages for AR measurements. There was no interaction ( P > 0.05) between cage type and LPS on response variables. At 4 woa, body ( P = 0.002) and bone ( P < 0.05) weight was higher for CON than FUR pullets, but this was reversed ( P < 0.01) at 16 woa. Pullets fed M LPS had higher ( P < 0.05) AR of Ca, whole body mineral density ( BoMD ), and whole body mineral content ( BoMC ) than pullets fed F LPS. However, pullets fed F LPS had higher ( P < 0.05) femur bone mineral density ( BMD ) and tended ( P = 0.059) to have higher tibia bone breaking strength ( BBS ) than pullets fed M LPS at 16 woa. Pullets reared in CON cages had higher ( P < 0.05) AR of Ca than FUR pullets. At 4 woa, CON pullets had lower ( P < 0.05) femur and tibia BMD but higher tibia (93 vs. 83 N P = 0.012) BBS than FUR pullets. However, at 16 woa, FUR pullets had higher ( P < 0.05) BoMD, BoMC, and tibia BBS than CON pullets. In conclusions, cage type and dietary LPS had independent effects on Ca utilization and skeletal development. Despite poor Ca retention, FUR caged pullets showed improved bone quality at 16 woa. Finer LPS improved femur mineral density suggesting coarser LPS had limited effects on pullet bone quality.

Cage type and mineral nutrition had independent impact on skeletal development in Lohmann LSL-Lite pullets from hatch to 16 weeks of age

“…A total of 3,420 Lohmann LSL-lite day-old pullets (Archer's Hatchery, ON, Canada) were placed in CON or FUR cages. The details of cage were presented in our previous publication ( Khanal et al., 2020a ). Briefly, the dimension (length × breadth × height) of CON (Ford Dickinson Inc., Mitchell, ON, Canada) and FUR (Farmer Automatic, Clark Ag Systems, ON, Canada) were respectively 76 cm × 71 cm × 46 cm and 239 cm × 80 cm × 75 cm with total floor space area 5,396 and 19,120 cm 2 .…”

“…The whole body, femur and tibia MD and content were determined using dual energy X-ray absorptiometry (DEXA) as described in Khanal et al. ( 2020a ). Briefly, the pullets were first evaluated for whole body MD and content.…”

“…Multiple factors such as early start of lay and long lay cycle increase pull out of calcium (Ca) from bones ( Korver, 2020 ). For example, a white hen lays 340 eggs by 72 wk of age ( Lohmann, 2016 ), based on fact that eggshell contain 2.5 g of Ca and whole-body Ca of a pullet at onset of lay is 25 g ( Khanal et al., 2020a ). It follows that she will draw more than 30 times her body Ca for eggshell formation over the course of lay cycle ( Kim et al., 2012 ).…”

“…The bone quality in layer is influenced by housing and nutrition ( Fleming et al., 2006 ). Provision of physical activities in the housing environment has been shown to influence skeletal development in pullets ( Regmi et al., 2015 ; Casey-Trott et al., 2017a ; Khanal et al., 2020a ). Enriched or furnished cages (FUR) in comparison to conventional cages (CON) provide more space for movement, more opportunity for load bearing exercise such as perching, jumping etc., and support for expression of normal behavior such as scratching, perching, preening etc.…”

“…But there is limited knowledge regarding increased dietary Ca, P and VitD 3 during rearing on skeletal development in pullets. Our recent study ( Khanal et al., 2020a ) showed that pullets reared in FUR cages developed leg bones with higher bone MD and content (MC) than pullets reared in CON cages. This suggested that the cage type might potentially interact with dietary minerals on bone mineralization.…”