Bone Breaking Strength Research Articles

Regulation of bone phosphorus retention and bone development possibly by related hormones and local bone-derived regulators in broiler chicks

BackgroundPhosphorus is essential for bone mineralization in broilers, however, the underlying mechanisms remain unclear. We aimed to investigate whether bone phosphorus retention and bone development might be regulated by related hormones and local bone-derived regulators in broilers.MethodsBroilers were fed diets containing different levels of non-phytate phosphorus (NPP) 0.15%, 0.25%, 0.35%, 0.45% and 0.55% or 0.15%, 0.22%, 0.29%, 0.36% and 0.43% from 1 to 21 or 22 to 42 days of age. Serum and tibia samples were collected for determinations of bone phosphorus retention and bone development parameters, related hormones and local bone-derived regulators of broiler chickens on d 14, 28 and 42, respectively.ResultsTibia ash phosphorus, total phosphorus accumulation in tibia ash (TPTA), bone mineral concentration (BMC), bone mineral density (BMD), bone breaking strength (BBS), and ash on d 14, 28 or 42, serum 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) on d 28 and 42, mRNA expressions of tibia fibroblast growth factor 23 (FGF23) and dentin matrix protein 1 (DMP1) on d 14 and 28 increased linearly or quadratically (P < 0.05), while serum parathyroid hormone (PTH) on d 28, tibia alkaline phosphatase (ALP) on d 14, 28 and 42, bone gal protein (BGP) on d 14, and mRNA expression of tibia phosphate-regulating gene with homologies to endopeptidases on the X chromosome (PHEX) on d 14 and 28 decreased linearly or quadratically (P < 0.04) as dietary NPP level increased. TPTA, BMC, BMD, and ash on d 28 and 42, BBS on d 28, and ash phosphorus on d 42 were positively correlated (r = 0.389 to 0.486, P < 0.03) with serum 1,25(OH)2D3. All of the above parameters were positively correlated (r = 0.380 to 0.689, P < 0.05) with tibia DMP1 mRNA expression on d 14, 28 and 42, but negatively correlated (r = − 0.609 to − 0.538, P < 0.02) with serum PTH on d 28, tibia ALP on d 14, 28 and 42, and BGP on d 14. TPTA, BMC and ash on d 14 and BMD on d 28 were negatively correlated (r = − 0.397 to − 0.362, P < 0.03) with tibia PHEX mRNA expression, and BMD on d 28 was positively correlated (r = 0.384, P = 0.04) with tibia FGF23 mRNA expression.ConclusionsThese results suggested that bone phosphorus retention and bone development parameters had moderate to strong correlations with serum PTH and 1,25(OH)2D3 and tibia DMP1, PHEX, FGF23, ALP and BGP in broilers during the whole growth period, and thus they might be partly regulated by these related hormones and local bone-derived regulators.

Effect of crushed sugarcane on performance, bone characteristics and intestinal morphology of free-range chicken lines

The objective of this study was to evaluate the effect of different levels of crushed sugarcane in the diet on the performance, bone characteristics and intestinal morphology of slow-growing broiler strains. A total of 448 chickens at 35 days of age were allotted to two randomized blocks in a 4×2 factorial arrangement (levels of feed replacement with crushed sugarcane, on a fresh-matter basis: 0, 15, 30, and 45%) and two strains (Pesadão and Label Rouge (LR)). Two replicates were used per block over time (containing the treatments and the strains), and 14 individuals were used per experimental unit. Weight gain and feed intake decreased linearly in response to the increasing sugarcane levels. Feed intake was higher in the Pesadão strain than in LR. Chicken foot weight was lower in Pesadão than in LR. There were no effects of sugarcane levels or strains on the tarsometatarsal bone weight, breaking strength, maximum load and deformation. The dry matter (DM) content of the tarsometatarsal bone was lower in LR than in Pesadão. The replacement of feed with sugarcane induced a linear increase in bone ash content and a decrease in bone phosphorus and calcium contents. Label Rouge chickens showed a greater crypt depth and lower values of villus/crypt ratio and mucosal layer thickness. The performance and intestinal morphology of broiler chickens are negatively affected by increasing sugarcane levels in the diet. In addition, the increasing intake of sugarcane changes the bone mineral composition without reducing mechanical resistance, in both the Pesadão and Label Rouge strains.

In ovo feeding with 25-hydroxycholecalciferol influences bone mineral density of chicks

The purpose of this study was to determine if in ovo feeding with 25(OH)D3 could influence the incubation parameters of bone mineral composition, mineral density, and bone breaking strength in post-hatch broilers. Fertile eggs from Cobb® broiler breeders were either non-injected or injected with 0, 1.2, 2.4, or 3.6 μg of 25(OH)D3/100 μL olive oil at eight days of incubation. The data were subjected to variance analysis using the General Linear Model procedure (GLM) of SAS®. There was a [...]

Identification and Functional Annotation of Genes Related to Bone Stability in Laying Hens Using Random Forests.

Skeletal disorders, including fractures and osteoporosis, in laying hens cause major welfare and economic problems. Although genetics have been shown to play a key role in bone integrity, little is yet known about the underlying genetic architecture of the traits. This study aimed to identify genes associated with bone breaking strength and bone mineral density of the tibiotarsus and the humerus in laying hens. Potentially informative single nucleotide polymorphisms (SNP) were identified using Random Forests classification. We then searched for genes known to be related to bone stability in close proximity to the SNPs and identified 16 potential candidates. Some of them had human orthologues. Based on our findings, we can support the assumption that multiple genes determine bone strength, with each of them having a rather small effect, as illustrated by our SNP effect estimates. Furthermore, the enrichment analysis showed that some of these candidates are involved in metabolic pathways critical for bone integrity. In conclusion, the identified candidates represent genes that may play a role in the bone integrity of chickens. Although further studies are needed to determine causality, the genes reported here are promising in terms of alleviating bone disorders in laying hens.

Pinus roxburghii alleviates bone porosity and loss in postmenopausal osteoporosis by regulating estrogen, calcium homeostasis and receptor activator of nuclear factor-κB, osteoprotegerin, cathepsin bone markers.

The study was aimed to evaluate the potential of hydroalcoholic extract of Pinus roxburghii (PRE) stem bark in post-menopausal osteoporosis and its underlying mechanisms. In silico docking of the markers was done using AutoDock version 4.2. for molecular targets: receptor activator of nuclear factor-κB (RANK), osteoprotegerin (OPG) and Cathepsin. Female Wistar rats of bodyweight 200-250 g were employed and surgical ovariectomy (OVX) was performed. PRE was administered at a dose of 100 and 200 mg/kg whereas standard drug, raloxifene given at 1 mg/kg orally for eight weeks. PRE (20 and 40 µg/mL) significantly increased the cellular proliferation in osteoblastic UMR cell lines 11.58 and 15.09% respectively. Eight weeks after surgical removal of ovaries, a significant bone porosity was confirmed by modulation in bone breaking strength of tibia, lumber, and femur; bone mineral density (BMD), calcium, phosphorus, hydroxyproline levels in OVX group. Treatment with PRE 100 and 200 mg/kg significantly restored the bone loss. Real-time polymerase chain reaction (RT-PCR) analysis of molecular markers RANK, OPG and cathepsin and histology also confirmed the attenuation of bone loss. The quantification of quercetin, gallic acid, caffeic acid, catechin, tannic acid and ascorbic acid was done by high-performance liquid chromatography (HPLC) and high performance thin layer chromatography. P. roxburghii produced anti-osteoporotic effect possibly due to estrogenic modulation, and improved bone remodeling.

No evidence that selection for egg production persistency causes loss of bone quality in laying hens

BackgroundThe physiological adaptations that have evolved for egg laying make hens susceptible to bone fractures and keel bone damage. In modern laying hen breeds, longer periods of egg laying could result in a greater risk of poor bone quality, and selection for increased egg production has frequently been stated to be a cause. However, the existing literature does not support this hypothesis. To test the hypothesis that egg production is associated with quality, breaking strength and density of bone, genetic correlations between these traits were estimated in White Leghorn and Rhode Island Red breeds. Genetic correlations of cortical and medullary bone material chemical properties with bone quality were also estimated, in order to identify methods to improve bone quality with appropriately targeted measurement of key traits.ResultsEstimates of heritability for bone quality traits were moderate (0.19–0.59) for both White Leghorn and Rhode Island Red breeds, except for the keel bone trait, which had a heritability estimate equal to zero. There was no evidence for genetic or phenotypic relationships between post-peak egg production and bone quality. In the White Leghorn breed, the estimate of the genetic correlation between pre-peak production/age at first egg and bone quality was significant and negative (− 0.7 to − 0.4). Estimates of heritability of thermogravimetric measurements of tibial medullary bone mineralisation were significant (0.18–0.41), as were estimates of their genetic correlations with tibia breaking strength and density (0.6–0.9).ConclusionsThe low genetic correlation of post-peak egg production with bone quality suggests that selection for increased persistency of egg production may not adversely affect bone quality. Onset of puberty and mineralisation of the medullary bone, which is a specialised adaptation for egg laying, were identified as important factors associated with the quality of the skeleton later during egg production. These are traits for which genetic, as well as environmental and management factors can positively impact the overall quality of the skeleton of laying hens.

Effects of the housing environment and laying hen strain on tibia and femur bone properties of different laying phases of Hy-Line hens

This study aimed to determine the effect of the housing environment and laying hen strain on tibia and femur properties. A 3 × 2 factorial arrangement of 3 housing environments (conventional cages [CC], enriched colony cages [EC], and free range [FR]) and 2 laying hen strains (Hy-Line W-36 [W-36] and Hy-Line Brown [HB]) in a completely randomized design was conducted from 32 to 85 wk of age. Six left tibias were collected at 8 different time points (38, 45, 52, 59, 65, 72, 79, and 85 wk of age), whereas 6 left femurs were collected at 3 time points (38, 65, and 85 wk of age). Tibias were evaluated for tibia breaking strength (TBS) and ash percentage, whereas femurs were evaluated for bone mineral density (BMD), bone mineral content, bone volume as a fraction tissue volume, and porosity percentage from total, cortical, medullary, and trabecular bones. The higher TBS (P = 0.0005) and ash percentage (P = 0.045) was observed in hens raised in FR systems compared with those raised in the CC. Overall, TBS of W-36 hens was significantly greater than that of HB hens (P < 0.0001); however, there was no difference in the ash percentage between the strains (P > 0.05). An interaction between the housing environment and hen strain was observed for BMD (P = 0.04), wherein W-36 hens raised in the FR system had higher BMD than HB hens. Similarly, hens raised in FR systems had higher trabecular bone volume than those raised in CC (P = 0.022). Hen strain influenced total and cortical bone properties: BMD, bone volume as a fraction tissue volume, and porosity percentage, wherein W-36 hens had better properties than HB hens (P < 0.05). Trabecular BMD was higher in W-36 hens than in HB hens (P = 0.04), whereas bone volume was higher in HB hens (P < 0.0001). The results suggest that raising laying hens in alternative housing systems that have provision for exercise such as FR reduces structural bone loss, stimulate structural bone formation, and improve breaking strength of bones; however, it varies with the strain.

Effect of Dietary Supplementation of Organic Trace Minerals at Reduced Concentrations on Performance, Bone Mineralization, and Antioxidant Variables in Broiler Chicken Reared in Two Different Seasons in a Tropical Region

Two experiments were conducted to study the performance, antioxidant activity, and bone mineral variables in broilers fed organic trace minerals (OTM) at lowered concentrations in the diet. In experiment 1, a total of 1500 day-old broiler male chicks were randomly distributed into six groups with 10 replicates of 25 chicks each and housed in floor pens (1.90 × 1.22m). One group was fed the maize-soybean meal-based control diet, supplemented with inorganic trace mineral (ITM) premix containing Mn, Zn, Fe, Cu, Se, and Cr at 50, 45, 40, 7.5, 0.30, and 0.25mg/kg, respectively. The remaining groups of chicks were fed the diets, where the ITM premix was replaced with OTM mix so as to provide the respective minerals at graded levels in the diet (100, 75, 50, 40, and 30% of the control diet). Similarly, in experiment II, a total of 1350 day-old male broiler chicks were divided at random into six groups with 9 replicates of 25 chicks each and fed the maize-soybean meal-based control diet having ITM at levels similar to those of experiment I or the test diets, where the ITM was replaced with OTM so as to provide the minerals at 100, 80, 60, 40, and 20% of the ITM-based control diet. Each diet was fed ad libitum from 0 to 42days of age. The body weight gain, feed intake, and feed efficiency were not affected by supplementing OTM at 30 and 20% in experiments I and II, respectively. Slaughter variables, activities of glutathione peroxidase and super oxide dismutase, and lipid peroxidation and ferric reducing activity in serum were not affected by supplementing OTM at the lowest level of 20% in the diet. Similarly, bone-breaking strength, ash, and Mn contents were not affected by supplementing OTM at 20% of the mineral concentration in control diet containing ITM. Deposition of Ca, P, Cu, and Fe in tibia ash increased with increased concentration of OTM in the diet. However, Zn content in tibia ash reduced with reduction in OTM level in the diet. Based on the results, it is concluded that trace mineral supplementation in organic form even at 20% of the concentration recommended for ITM may be sufficient in maize-soybean meal-based diet to support the optimum growth, bone ash, bone strength, and serum antioxidant status in commercial broilers.

Effect of Xylo-Oligosaccharides Supplementation by Drinking Water on the Bone Properties and Related Calcium Transporters in Growing Mice.

Xylo-oligosaccharides (XOS), non-digestible oligosaccharides, have the potential to regulate intestinal microorganisms, and thus, improve host health, but little evidence exists for the prebiotic effects on bone health. This study evaluates the dose-response effect of XOS supplementation on bone properties, the morphology of the intestine, cecum pH, and cecum wall weight, as well as the related calcium transporters. Ninety-six 28-day-old male mice were randomized into one of four groups, fed the same commercial diet, and given different types of deionized water containing 0, 1, 2, or 4% XOS by concentration for 30 days. Eight mice were randomly selected to accomplish particular tasks every 10 days. No significant differences in serum Ca and P levels and growth performance were observed among the four studied groups. XOS intervention significantly decreased cecum pH and increased cecum wall weight in a dose-dependent manner. At the late growth stage, compared with 0% XOS, the bone mineral density (BMD) and bone-breaking strength in 4% XOS were significantly higher. The bone crystallinity with 4% XOS, measured by Raman spectrum, was significantly enhanced compared to that with 0% XOS during later growth. The villus height and villus height to crypt depth (VH:CD) were enhanced with an increase of XOS concentration during the later stage of growth. The expression of transient receptor potential vanillin receptor 6 (TRPV6) and Na+/Ca2+ exchanger 1 (NCX1) in the duodenum were enhanced by XOS supplementation. XOS exerted a positive influence on bone properties by decreasing the cecum pH, increasing the cecum wall and villus structure, and upregulating the expression of related calcium transporters.

Effect of graded levels of Imbrasia belina meal on blood lipid profile, bone morphometric and mineral content of broiler chickens

The effect of increasing dietary levels of Imbrasia belina worm meal on blood lipid profile, bone morphometric and mineral content in Arbor acres broiler chicks were assessed. A total of 360-day old chicks were randomly allocated to 4 dietary treatments, with each treatment group replicated 6 times (n = 15/replicate). The inclusion levels of the I. belina worm meal in the diets were 0 % (Treatment 1= control), 4 % (Treatment 2), 8 % (Treatment 3) and 12 % (Treatment 4). A 3-phase feeding program of starter (0−14d), grower (15−28d), and finisher (29−35d) was employed for the study. Total cholesterol (TC), triglycerides (TGL), high density lipoprotein (HDL), low density lipoprotein (LDL), bone morphometrics and mineral content were recorded at the end of study. There was no significant difference of total cholesterol (CHOL), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) concentration in all the treatments. However, significant concentrations were observed in triglycerides (TGL) and T3 showed highest levels compared to other treatments, at 35 days of age. The dietary inclusion levels of Imbrasia belina had no effect on femur weight, width, relative bone density, and bone breaking strength. However, the significant difference was observed on femur length, robusticity index and ash percentage. Also, broiler chickens fed T1 (6.62 g/100 g, 15.23 g/100 g dry matter) had the highest femur Ca and P content. Femur Z content of broilers fed T4 (24.08 mg/100 g dry matter) was highest. The correlation analyses showed significant moderate relationships between ash and femur weight, but however significant positive relationships with calcium, magnesium, manganese and zinc. More so, the correlation between femur strength and calcium and phosphorous was significant positive with a higher magnitude. The result of this study suggests that I. belina meal up to 12 % can be effectively utilized in broiler diets without any adverse effect on and bone mineral properties.

Effect of dietary calcium or phosphorus deficiency on bone development and related calcium or phosphorus metabolic utilization parameters of broilers from 22 to 42 days of age

This experiment was conducted to investigate the effect of dietary calcium (Ca) or phosphorus (P) deficiency on bone development and related Ca or P metabolic utilization parameters of broilers from 22 to 42 days of age based on our previous study, which indicated that dietary Ca or P deficiency impaired the bone development by regulating related Ca or P metabolic utilization parameters of broilers from 1 to 21 days of age. A total of 504 one-day-old Arbor Acres male broilers were randomly assigned to 1 of 4 treatments with 7 replicates in a completely randomized design, and fed the normal control and Ca- or P-deficient diets from 1 to 21 days of age. At 22 days of age, the broilers were further fed the normal control diet (0.90% Ca+0.35% non-phytate P (NPP)), the P-deficient diet (0.90% Ca+0.18% NPP), the Ca-deficient diet (0.30% Ca+0.35% NPP) or the Ca and P-deficient diet (0.30% Ca+0.18% NPP), respectively. The results showed that dietary Ca or P deficiency decreased (P<0.05) tibia bone mineral density (BMD), bone breaking strength (BBS), ash content, tibia ash Ca content and serum P content on days 28 and 42, but increased (P<0.05) tibia alkaline phosphatase (ALP) activity of broilers on day 42 compared with the control group. Furthermore, the broilers fed the P-deficient diet had the lowest (P<0.05) tibia BMD, BBS, ash content, serum P content and the highest (P<0.05) serum Ca content on day 28 compared with those fed the Ca-deficient or Ca and P-deficient diets. The results from the present study indicated that the bone development and related Ca or P metabolic utilization parameters of broilers were the most sensitive to dietary P deficiency, followed by dietary Ca deficiency or Ca and P-deficiency; dietary Ca or P deficiency impaired the bone development possibly by regulating serum Ca and P contents as well as tibia Ca content and ALP activity of broilers from 22 to 42 days of age.

Genome-wide association study of bone quality and feed efficiency-related traits in Pekin ducks

Feeding and bone traits are vital for breeding and reproduction in the commercial duck industry. In this study, we performed a genome-wide association study for feeding and bone traits in a population of 540 lean-type Pekin ducks, followed by genotyping-by-sequencing procedures. The genetic parameters of feeding and bone traits were also estimated using genomic information. In total, seventy-eight significant SNPs were determined, and eleven of them reached the genome-wide significant level for 7 traits except for body weight at 42-day old. A peak of genome-wide significant SNPs was detected on chromosome 2 for feed conversion ratio (P-value = 7.46E-11), and the top SNP (P-value = 2.23E-08) for bone-breaking strength was also obtained in the upstream of gene RAPGEF5. This study provided a list of novel markers and candidate genes associated with feeding and bone traits in Pekin ducks, which could contribute to the genetic selection in duck breeding.

Egg Production and Bone Stability of Local Chicken Breeds and Their Crosses Fed with Faba Beans.

Simple SummaryPoultry production systems are currently facing important issues like animal welfare, the environmental impact of soy imports from overseas and the decline in genetic diversity. The current study aims at testing an alternative production system that could provide niche markets with regional poultry products. Six different chicken genotypes were tested in this study regarding egg production traits and bone stability. As a regional alternative to soy, two varieties of locally grown faba beans have been used in the animals’ diets. A limited adverse effect of the vicin-rich faba bean diet on egg weight was observed. The crossbred chicken of the local breed Bresse Gauloise with the commercial laying hen White Rock seems to be the most promising.Poultry production is raising concerns within the public regarding the practice of culling day-old chicks and the importation of soy from overseas for feedstuff. Therefore, an alternative approach to poultry production was tested. In two consecutive experiments, two traditional chicken breeds, Vorwerkhuhn and Bresse Gauloise, and White Rock as a commercial layer genotype as well as crossbreds thereof were fed diets containing either 20% vicin-rich or vicin-poor faba beans, though addressing both subjects of debate. Hen performance traits and bone stability were recorded. All parameters were considerably influenced by the genotype with White Rock showing the significantly highest (p < 0.05) laying performance (99.4% peak production) and mean egg weights (56.6 g) of the purebreds, but the lowest bone breaking strength (tibiotarsus 197.2 N, humerus 230.2 N). Regarding crossbreds, the Bresse Gauloise × White Rock cross performed best (peak production 98.1%, mean egg weight 58.0 g). However, only limited dietary effects were found as only the feeding of 20% vicin-rich faba beans led to a significant reduction of egg weights of at most 1.1 g (p < 0.05) and to a significant reduction of the shell stability in the crossbred genotypes. In terms of dual-purpose usage, crossing of Bresse Gauloise with White Rock seems to be the most promising variant studied here.

Efficacy and stability of a novel silica supplement for improving bone development in broilers

ABSTRACT 1. The essentiality of silicon for skeletal development has been established, but the adequacy of bioavailable silicon supply in broiler diets has not been considered for 30 years, despite average daily weight gain of birds increasing by almost a third over that time. Therefore, two studies were undertaken to investigate whether modern strains of broiler chicken benefit from diet supplementation with bioavailable silica. 2. Trial 1 was a 2x2x2 factorial study where six replicate pens of seven chicks were fed one of the eight freshly prepared diets from hatch to 21 days of age, with bodyweight gain and feed intake recorded weekly. Diets combined the following factors: silicon supplement fed at 0 ppm or 1000 ppm, phytase levels of either 0 FTU/kg or 1500 FTU/kg and either 0.6% or 0.7% Ca. Tibia were analysed for bone breaking strength, extent of tibial dyschondroplasia and feet measured for bone ash and pododermatitis score. 3. Trial 2 used a 0.7% Ca with 1500 FTU phytase diet as the control and compared this with the same diet containing either 1000 ppm silicon (MONO-Si) freshly added each week or 1000 ppm silicon added in a single, advance-prepared batch per feeding phase. Each diet was fed to nine pens of seven birds from 0 to 35 d with feed consumption and weight recorded weekly. Two birds per pen were euthanised on d 14, 21 and 35 and tibias collected for measurement of bone breaking strength, ash and mineral content. Serum was collected for Si content. 4. Univariate analysis of means from each trial showed that silica supplementation improved bird weight gain over the starter phase, though there was no effect on feed conversion. 5. Bone strength improved with added silica in both studies, without affecting bone mineral content; indicating that modern strains of broiler may require dietary supplementation with bioavailable silicon.

Effects of normal and low calcium and phosphorus levels and 25-hydroxycholecalciferol supplementation on performance, serum antioxidant status, meat quality, and bone properties of broilers.

To determine the effects of normal and low dietary calcium (Ca) and phosphorus (P) levels and 25-hydroxycholecalciferol (25-OH-D3) supplementation on performance, serum antioxidant status, meat quality, and bone properties of broilers, 224 1-day-old Arbor Acre male broilers were used in this study. Broilers were allotted randomly to 1 of 4 treatments in a 2 × 2 factorial arrangement that included normal or low Ca and P diet with or without 69 μg/kg 25-OH-D3. The trial consists of a starter phase from day 1 to 21 and a grower phase from day 22 to 42. Dietary 25-OH-D3 supplementation increased (P < 0.05) average daily weight gain from day 22 to 42 and decreased feed conversation ratio from day 22 to 42 and day 0 to 42. On day 21, 25-OH-D3 increased serum concentrations of total antioxidant capacity (T-AOC), catalase (CAT), and glutathione peroxidase in broilers fed low Ca and P diet (Interaction, P < 0.05). 25-hydroxycholecalciferol significantly decreased serum malondialdehyde concentration. Dietary Ca and P deficiencies significantly decreased serum Ca and P concentrations and increased serum parathyroid hormone (PTH) concentration, and serum Ca and 25-OH-D3 concentrations were significantly increased by 25-OH-D3 supplementation. On day 42, serum T-AOC and CAT concentrations were decreased by dietary Ca and P deficiencies without 25-OH-D3 (Interaction, P < 0.05) and unaffected by dietary Ca and P deficiencies with 25-OH-D3. Dietary Ca and P deficiencies significantly decreased Ca, P, and alkaline phosphatase concentrations and increased PTH concentration in serum. Dietary 25-OH-D3 increased (P < 0.05) serum Ca and 25-OH-D3 concentrations and decreased (P < 0.05) serum tartrate-resistant acid phosphatase concentration. The interaction between CaP level and 25-OH-D3 was observed (P < 0.05) for tibial Ca content and femoral bone density. 25-hydroxycholecalciferol significantly increased tibial breaking strength. These data indicated that 25-OH-D3 supplementation at 69 μg/kg increased growth performance in some periods, enhanced serum antioxidant capacity, and improved bone mineralization and breaking strength of broilers.

Strain differences and effects of different stocking densities during rearing on the musculoskeletal development of pullets

There are few published studies on the effect of stocking density (SD) of pullets, particularly between different genetic lines. The objectives of this study were to determine if strain or SD affects musculoskeletal development of pullets and determine any impact on the productivity and keel bone health of adult hens. Lohmann Selected Leghorn Lite (LSL), Dekalb White (DW), and Lohmann Brown (LB) pullets were reared at 4 different SD (247 cm2/bird, 270 cm2/bird, 299 cm2/bird, and 335 cm2/bird) in large cages furnished with elevated perches and a platform. At 16 wk of age, the keel bone, the muscles of the breast, wings, and legs, and the long bones of the wings and legs were collected to compare keel bone development, muscle growth, and bone breaking strength (BBS) between strain (adjusted for bodyweight) and SD treatments. Stocking density did not have an effect on the metasternum length, height, or area of the keel bone, the weights of the bicep brachii, pectoralis major or pectoralis minor, or the BBS of any of the selected bones. However, strain differences were found for all keel bone characteristics, all muscle weights, and the majority of BBS measures. The keel metasternum, height, and overall area of the keel bone were found to be smaller in LB pullets compared with LSL and DW pullets (P < 0.0001); however, cartilage length and overall percentage of the cartilage present on the keel bone was greatest in LB pullets (P < 0.0001). Leg muscles were heaviest in LB pullets (P < 0.05); however, breast muscles were heavier in LSL and DW pullets (P < 0.0001). Lohmann Brown pullets had lower BBS of the tibia (P < 0.0001) and femur (P < 0.0001) compared with LSL and DW pullets, whereas DW pullets had greater BBS of the humerus (P = 0.033). Additionally, there was a higher prevalence of keel bone fractures at 50 wk of age in LB hens compared with DW (P = 0.0144). Overall, SD during rearing used in this study had little impact on the musculoskeletal growth of pullets; however, significant differences were found between strains which may reflect strain-specific behavior. Additionally, differences in keel bone development between strains may lead to differences in keel bone damage in adult hens.

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

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.

Relationship between Bone Stability and Egg Production in Genetically Divergent Chicken Layer Lines.

Simple SummaryBrittle or fractured bones due to continuous demineralisation cause major welfare and economic problems in laying hens. Bone weakness in laying hens is frequently attributed to long-term selection for increased egg production, but this is controversially discussed in the scientific literature. We aimed at characterizing factors influencing the bone breaking strength of laying hens, focusing mainly on the effect of eggshell production. By examining four different chicken layer lines separately, a genetically diverse spectrum of laying hen origins was included in our study. It was shown that bone strength is primarily influenced by bone mineral density. A strong association between bone strength and eggshell production was not observed within each of the lines studied. This applied to all layer lines. Our results suggest that a high egg number does not generally impair bone stability within layer lines. Findings from this study contribute to the discussion on the improvement of bone stability in poultry breeding programs and thus lead to increased animal welfare in egg production.Impaired animal welfare due to skeletal disorders is likely one of the greatest issues currently facing the egg production industry. Reduced bone stability in laying hens is frequently attributed to long-term selection for increased egg production. The present study sought to analyse the relationship between bone stability traits and egg production. The study comprised four purebred layer lines, differing in their phylogenetic origin and performance level, providing extended insight into the phenotypic variability in bone characteristics in laying hens. Data collection included basic production parameters, bone morphometry, bone mineral density (BMD) and bone breaking strength (BBS) of the tibiotarsus and humerus. Using a multifactorial model and regression analyses, BMD proved to be of outstanding importance for bone stability. Only for the tibiotarsus were morphometric parameters and the bone weight associated with BBS. Within the chicken lines, no effect of total eggshell production on BBS or BMD could be detected, suggesting that a high egg yield itself is not necessarily a risk for poor bone health. Considering the complexity of osteoporosis, the estimated genetic parameters confirmed the importance of genetics in addressing the challenge of improving bone strength in layers.

Chickens in motion: Effects of egg production level and pen size on the motor abilities and bone stability of laying hens (Gallus gallus forma domestica)

Laying hens have undergone strong selection pressure for traits related to productivity in recent decades. This has led to an impressive increase in egg production but is also assumed to cause undesirable side effects, such as behavioural changes or increased bone damage. Resource trade-offs resulting from egg production might trigger such changes. Our hypothesis was that hens from lines selected for high levels of egg production need to conserve energy to maintain productivity by reducing locomotor activity. We further assumed that the reduced locomotor activity is accompanied by poorer motor coordination abilities. In addition to the performance level, phylogenetic origin has potential implications for behavioural and physiological differences. Thus, we compared hens from four purebred layer lines in a 2 × 2 model that differed in productivity levels (a line with high egg production (320 eggs/year) and a line with moderate egg production (200 eggs/year)) and phylogenetic origins (white and brown egg layer lines). Furthermore, hens of each line were kept in compartments of two different sizes (large, with stocking densities of 3.19 hens/m2; and small, with stocking densities of 5.94 hens/m2), to examine the effect of space and stocking density on the behaviour and bone strength of the hens. In total, we tested 742 chickens from the four different layer lines. We recorded their general locomotor activity in their home compartments and tested their motor coordination using a rotarod test. After the laying period, we examined the bone breaking strength of the tibiotarsi and the humeri from chickens of all four lines. The hens from both highly productive lines possessed poorer motor coordination than the hens from the moderately productive lines of corresponding phylogenetic origin. Furthermore, the hens from the brown egg-laying lines performed better than the hens from the white egg-laying lines. Compartment size had a positive effect on the motor coordination of the hens from the moderately productive lines and interacted with productivity. However, general locomotor activities were not different between the hens from lines with different productivities or of different phylogenetic origins. The hens from the moderately productive lines possessed higher bone breaking strengths than the hens from the highly productive lines within the phylogenetic groups. Our results show that the hens from the lines with high productivity have poorer motor coordination and lower bone breaking strength than the hens with moderate productivity. These results can help to gain further understanding of practical problems, such as the high prevalence of bone damage in laying hens.

Endogenous enzyme activities and tibia bone development of broiler chickens fed wheat-based diets supplemented with xylanase, β-glucanase and phytase.

ObjectiveThis study assessed the effect of different levels of xylanase, β-glucanase and phytase on intestinal enzyme activities and tibia bone development in broiler chickens fed wheat-based diets.MethodsTwelve experimental diets were formulated using a 3×2×2 factorial design (three doses of phytase and two doses of both xylanase and β-glucanase) and offered to 648 day-old Ross 308 male chicks having 6 replicates groups with 9 birds per replicate and lasted for 35 days.ResultsAn interaction between the enzymes products improved (p<0.01) the activity of chymotrypsin. Protein content at d 10 was highest (p<0.001) with addition of phytase while general proteolytic activity (GPA) (p<0.02) and lipase activity (p<0.001) were decreased. At d 24, there were improvements in protein content (p<0.01) and lipase (p<0.04) with supplementation of superdose phytase. Addition of superdose phytase decreased in chymotrypsin (p<0.02), trypsin (p<0.01) and GPA (p<0.001). The optimum dose of xylanase decreased the chymotrypsin activity (p = 0.05), while the GPA (p<0.001) was increased with the optimum level of β-glucanase. Superdose phytase supplementation at d 10 improved maltase (p = 0.05), sucrase (p<0.001) and alkaline phosphatase (p<0.001) activities in the jejunum while aminopeptidase activity was highest (p<0.005) with the low level of phytase. Protein content of jejunum mucosa was bigger (p<0.001) in birds fed superdose phytase while maltase activity (p<0.001) at d 24 was reduced by this treatment. Sucrase (p<0.04) and aminopeptidase activities (p<0.001) improved when diets supplemented with low levels of phytase. Tibia bone breaking strength was highest (p<0.04) with addition of low level of superdose phytase or optimum level of β-glucanase. Bone dry matter content decreased (p<0.04) when diets supplemented with phytase.ConclusionFrom the results obtained in this study, supplementation of superdose phytase was the most effective, however, the cost-benefit analysis of the use of such a dose needs to be evaluated.