Bone Breaking Strength Research Articles

Estimation of bone mineral density and breaking strength of laying hens based on scans of computed tomography for body composition analysis

ABSTRACT1. The objective of this study was to evaluate the prediction potential of a computer tomography (CT) data collection protocol for determining total body composition used for analysis of tibiotarsal bone quality features.2. The CT image acquisition was performed on 54 healthy TETRA SL genotype laying hens at 90 weeks of age as well as in the 69th week of the egg production period in vivo and their tibiotarsal bones, ex vivo.3. Breaking strengths and ash content of the tibiotarsal bones were estimated based on the calculated mineral density of skeletal and tibiotarsal bones by means of CT with an estimation accuracy R2 0.963 and 0.975, respectively.4. In conclusion, the current investigation demonstrated that the acquisition protocol of CT for total-body composition analysis has a good potential for measuring the mineral status and breaking strength of the reference bone in laying hen.

The influence of selected feed additives on mineral utilisation and bone characteristics in laying hens

Abstract The trial with 240 caged ISA Brown laying hens was performed to evaluate the effect of selected feed additives on mineral utilisation as well as biomechanical (breaking strength, yielding load, stiffness) and geometrical (cortex thickness, cross-section area, weight, length) indices of tibia and femur bones. At 26 wks of age the layers were randomly assigned to 10 treatments with 12 replicates (cages) of two birds. In the study a 2 × 5 experimental scheme was used i.e. to 70 wks of age, the layers were fed isocaloric and isonitrogenous experimental diets containing reduced (3.20%) or standard (3.70%) Ca level. The diets with both Ca levels were either not supplemented, or supplemented with the studied feed additives i.e. sodium butyrate, probiotic bacteria, herbal extract blend and chitosan. There were no statistically significant effects of the experimental factors on the indices of the tibia bones. However, the diet with reduced Ca level decreased bone breaking strength, yielding load, stiffness, and mineralisation of the femur bones (P<0.05). The majority of used feed supplements, i.e. probiotic, herb extracts, and chitosan, increased biomechanical indices (breaking strength and yielding load) and mineralisation of the femur bones (P<0.05). Neither dietary Ca level nor feed additives affected dry matter, organic matter, ether extract, N-free extracts, crude fibre and ash digestibility, and P retention and excretion; however, Ca excretion and retention was lower in the hens fed the diets with reduced Ca level (P<0.05). Relative Ca retention (Ca retained as % of Ca intake) was improved by diet supplementation with probiotic, herb extracts and chitosan (P<0.05). In conclusion, this study has shown that decreased Ca dietary level (3.20%) can negatively affect bone quality in layers, while probiotic, herb extracts and chitosan addition may improve the selected biomechanical indices of the femurs, irrespective of Ca dietary concentration.

Effect of different vitamin D3 metabolites on intestinal calcium homeostasis-related gene expression in broiler chickens

ABSTRACT The purpose of this study was to investigate the effects of vitamin D3 metabolites 1α-hydroxycholecalciferol (1α(OH)D3), 25-hydroxycholecalciferol (25(OH)2D3), and 1,25-dihydroxycholecalciferol (1,25(OH)2D3) on growth performance, bone quality, and intestinal calcium homeostasis-related gene expression in broiler chickens. One-day-old broilers were fed a basal diet and basal diet containing different vitamin D3 metabolites. The body weight, feed intake, and feed conversion ratio in control and experimental broilers were measured to assess the growth performance, mineral levels, and bone breaking strength. The duodenum [...]

Effect of threonine and potassium carbonate supplementation on performance, immune response and bone parameters of broiler chickens

ABSTRACTThis study aimed to investigate the effect of different levels of dietary threonine (i.e. 100%, 110% and 120% of Ross recommendations) and potassium (i.e. 0.85% and 0.94% of diet) on performance, immune response, and bone parameters broiler chickens. Three hundred one-day-old male broiler chickens (Ross 308) were randomly assigned to 1 of 6 dietary treatments in a completely randomized design with a 3 × 2 factorial arrangement. Growth performance was not affected by dietary treatments. Birds fed diet containing 120% threonine and high potassium level were exhibited a lower immune response to phytohemagglutinin-P (PHA-P) as compared to control group (P < .05). Addition of 120% threonine with 0.94% potassium decreased heterophil percentage and heterophil to lymphocyte ratio and increased lymphocyte percentage (P < .05). Tibia and femur width and ash, Ca and P percentage of tibia, and breaking strength of bones were not influenced by dietary potassium level, whereas the width of tibia and femur was increased in broiler chickens received diet containing 120% threonine and 0.94% potassium compared to control group (P < .05). It is concluded that broiler chickens FI during starter period, cell mediated immune response and blood hematology were influence by dietary threonine and potassium interaction.

Effects of dietary calcium and phosphorus deficiency and subsequent recovery on broiler chicken growth performance and bone characteristics

The ability of birds to modify dietary phosphorus utilisation when fed with low-phosphorus and calcium (Ca) diets was studied using different sequences of dietary phosphorus and Ca restriction (depletion) and recovery (repletion) during the grower and the finisher phases. A total of 3600 Ross 708 broilers were randomly divided into 10 replicate pens per treatment (60 per pen, six pens per block). Chicks were fed a common starter diet from days 0 to 10, then a grower control diet (C: 0.90% Ca, 0.39% non-phytate phosphorus, nPP), mid-level diet (M: 0.71% Ca, 0.35% nPP) or low Ca and nPP diet (L: 0.60% Ca, 0.30% nPP) from days 11 to 21, followed by a finisher diet C, M or L containing, respectively, 0.85%, 0.57% or 0.48% Ca and 0.35%, 0.29% or 0.24% nPP from days 22 to 37. Six treatment sequences were tested: CC, MM, LL, ML, LC and LM. Bone mineral content by dual-energy X-ray, tibia ash, toe ash weight and tibia breaking strength were measured on days 21 and 37. No significant effect was observed on growth performance throughout the experiment. Diet L reduced bone mineral content, breaking strength, tibia and toe ash by 9%, 13%, 11% and 10%, respectively, on day 21 (compared with diet C, for linear effect, P<0.05). On day 37, bone mineral content, breaking strength, tibia and toe ash remained lower compared with control values (CC v. MM v. LL, P<0.05 for linear and quadratic effects). Mineral depletion duration (ML v. LL) did not affect bone mineral status. Replenishing with the C diet during the finisher phase (LC) restored bone mineral content, tibia ash and toe ash weight better than the M diet did, but not to control levels (CC v. LC v. LM, for linear effect, P<0.05). These results confirm that dietary Ca and nPP may be reduced in the grower phase without affecting final growth performance or breaking strength as long as the finisher diet contains sufficient Ca and nPP. The practical applications of this strategy require further study in order to optimise the depletion and repletion steps.

Effects of Zinc Oxide Nanoparticles on Performance, Egg Quality, Tissue Zinc Content, Bone Parameters, and Antioxidative Status in Laying Hens.

The objective of this study was to observe the effects of dietary supplementation with zinc oxide nanoparticles (ZnO-NPs) on performance, egg quality, tissue Zn content, bone parameters, superoxide dismutase activity (SOD), and egg malondialdehyde (MDA) content in laying hens. A total of 288 laying hens at 64weeks of age were randomly assigned to 4 treatments, 6 replicates, with 12 birds each. Experimental diets included the based diet (without Zn supplementation), and basal diet supplemented with 40, 80, and 120mg Zn/kg from ZnO-NPs. Feed intake and egg mass were significantly higher in the 40 and 80 ZnO-NPs groups than the other groups. The birds in the 80 ZnO-NPs group had significantly higher egg product than the 120 ZnO-NPs and control groups. Egg shell thickness and shell strength significantly increased in the 40 and 80 ZnO-NPs groups. Moreover, Haugh unit significantly improved in the groups supplemented with ZnO-NPs, compared to the control group. Bone-breaking strength was significantly greater in the 80 ZnO-NPs group than the 120 ZnO-NPs and control groups. Also, ash weight was significantly greater in the 40 and 80 ZnO-NPs groups than the control group. There were significant differences among the groups in the Zn content in plasma, tibia, liver, pancreas, and egg. Relative to the control group, ZnO-NPs supplementation significantly increased the activities of SOD in the liver, pancreas, and plasma. The MDA content in egg was significantly reduced in the groups supplemented with ZnO-NPs. In conclusion, this study demonstrates that ZnO-NPs as dietary supplementation can improve the performance of laying hens, and levels of 40 to 80 ZnO-NPs are the optimal concentrations.

How bone stability in laying hens is affected by phylogenetic background and performance level

1. Bone stability of five purebred layer lines differing in performance efficiency and phylogenetic origin was investigated within two housing systems. 2. Hens were kept in single cages or floor pens until the end of the 74 th week of age. At that time, they were sacrificed and examined for humeral and tibial traits. 3. Within a phylogenetic group, hens of the low performing lines had higher bone breaking strengths compared to their high performing counterparts. The bone mineral density of the tibia was significantly lower in the high performing brown egg layers than in the low performing ones. 4. Within and among layer lines, birds in floor housing had significantly higher tibia and humerus breaking strengths as well as higher bone weights than caged hens. 5. The differences between the high and low performing layer lines suggest a negative association between egg laying performance and bone stability in laying hens, irrespective of their phylogenetic origin. Moreover, the results confirm the already known effect of the housing system on bone strength.

Opportunities for exercise during pullet rearing, Part I: Effect on the musculoskeletal characteristics of pullets

Increased load-bearing exercise improves bone quality characteristics in a variety of species, including laying hens. Providing increased opportunities for exercise during the pullet rearing phase, a period of substantial musculoskeletal growth, offers a proactive approach to reducing osteoporosis by improving bone composition. The main objective of this study was to determine whether differing opportunities for exercise during rearing influences pullet musculoskeletal characteristics. Two flock replicates of 588 Lohmann Selected Leghorn-Lite pullets were reared in either standard, conventional cages (Conv) or an aviary rearing system (Avi) from day-old chicks until 16 wk of age. The keel bone and the muscles and long bones of the wings and legs were collected at 16 wk to measure muscle growth differences between rearing treatments and quantify bone quality characteristics using quantitative computed tomography (QCT) and bone breaking strength (BBS) assessment. Keel bone characteristics and muscle weights were adjusted for BW and analyses for QCT and BBS included BW as a covariate. At 16 wk of age, rearing system had an effect on the majority of keel bone characteristics (P < 0.05). The length of the keel metasternum, caudal tip cartilage length, and the overall percentage of cartilage present on the keel at 16 wk was greater in the Avi pullets compared to the Conv pullets (P < 0.01). Wing and breast muscle weights of the Avi pullets were greater than the Conv pullets (P < 0.001), but leg muscle weights were greater in the Conv pullets (P = 0.026). Avi pullets had greater total bone density, total cross-sectional area, cortical cross-sectional area, total bone mineral content, and cortical bone mineral content than Conv pullets for the radius, humerus, and tibia (P < 0.001). Avi pullets had greater BBS compared to the Conv pullets for the radius, humerus, and tibia (P < 0.01). Increased opportunities for exercise offered by the aviary rearing system increased muscle and bone growth characteristics in pullets at 16 wk of age.

Opportunities for exercise during pullet rearing, Part II: Long-term effects on bone characteristics of adult laying hens at the end-of-lay

Osteoporosis in laying hens has been a production and welfare concern for several decades. The objective of this study was to determine whether differing opportunities for exercise during pullet rearing influences long-term bone quality characteristics in end-of-lay hens. A secondary objective was to assess whether differing opportunities for exercise in adult housing systems alters bone quality characteristics in end-of-lay hens. Four flock replicates of 588 Lohmann Selected Leghorn-Lite pullets were reared in either conventional cages (Conv) or an aviary rearing system (Avi) and placed into conventional cages (CC), 30-bird furnished cages (FC-S), or 60-bird furnished cages (FC-L) for adult housing. Wing and leg bones were collected at the end-of-lay to quantify bone composition and strength using quantitative computed tomography and bone breaking strength (BBS). At the end-of-lay, Avi hens had greater total and cortical cross-sectional area (P < 0.05) for the radius and tibia, greater total bone mineral content of the radius (P < 0.001), and greater tibial cortical bone mineral content (P = 0.029) than the Conv hens; however, total bone mineral density of the radius (P < 0.001) and cortical bone mineral density of the radius and tibia (P < 0.001) were greater in the Conv hens. Hens in the FC-L had greater total bone mineral density for the radius and tibia (P < 0.05) and greater trabecular bone mineral density for the radius (P = 0.027), compared to hens in the FC-S and CC. Total bone mineral content of the tibia (P = 0.030) and cortical bone mineral content of the radius (P = 0.030) and tibia (P = 0.013) were greater in the FC-L compared to the CC. The humerus of Conv hens had greater BBS than the Avi hens (P < 0.001), and the tibiae of FC-L and FC-S hens had greater BBS than CC hens (P = 0.006). Increased opportunities for exercise offered by the aviary rearing system provided improved bone quality characteristics lasting through to the end-of-lay.

Effects of a dietary supplementation with zinc oxide nanoparticles, compared to zinc oxide and zinc methionine, on performance, egg quality, and zinc status of laying hens

An experiment was conducted to investigate the effect of diets supplemented with different Zn sources on performance, egg quality, bone parameters, Zn status, superoxide dismutase (SOD) activity, and egg malondialdehyde (MDA) content in laying hens. A total of 192 laying hens at 52 wk of age, with the initial average body weight of 1.53 ± 0.02kg, were randomly assigned to 4 treatments with 4 replicate cages and 12 laying hens per cage. Dietary treatments included the corn-soybean meal based diet (without Zn supplementation), and basal diet supplemented with 80mg Zn/kg diet from Zn oxide-nanoparticles (ZnO-NP), Zn oxide, and Zn-Met. The results showed that dietary Zn supplementation had no effect on feed intake, feed conversion ratio, live body weight, and egg loss. However, the greatest egg production and egg weight observed in ZnO-NP and Zn-Met treatments respectively (P < 0.05). Laying hens fed diets supplemented with ZnO-NP and Zn-Met had a greater egg mass compared to other treatments (P <0.05). Overall, Zn supplementation increased egg shell weight and Haugh unit (P <0.05). Dietary ZnO-NP supplementation increased egg shell thickness and egg shell strength, as compared to control (P < 0.05). The bone breaking strength and ash weight was greater in ZnO-NP and Zn-Met treatments, respectively (P < 0.05). The Zn deposition in tibia, liver, pancreas, and egg was greater in laying hens fed ZnO-NP and Zn-Met (P < 0.01). Plasma Zn status was not influenced by treatments. In treatments supplemented with ZnO-NP and Zn-Met, the SOD in the liver and pancreas were greater than the other treatments (P < 0.01). The MDA content in egg was reduced in treatments supplemented with Zn (P < 0.01). In conclusion, this study has shown that supplementation of a diet with ZnO-NP be a suitable source of zinc for laying hens.

Increased iron level in phytase-supplemented diets reduces performance and nutrient utilisation in broiler chickens

ABSTRACT1. The effect of different levels of dietary iron on phytase activity and its subsequent effect on broiler performance were investigated in a 3 × 2 factorial arrangement. A total of 360 day-old Ross 308 male broiler chicks were distributed to 6 experimental diets, formulated with three levels of Fe (60, 80 and 100 mg/kg) and two levels of phytase (0 and 500 FTU/kg).2. Phytase supplemented to mid-Fe diets increased feed consumption more than the non-supplemented diet at d 24. From hatch to d 35, Fe × phytase interaction significantly influenced the feed intake (FI), body weight gain (BWG) and feed conversion ratio (FCR). The high-Fe diet supplemented with phytase significantly reduced FI and BWG of broilers than those supplemented with low- or mid-Fe diets. The overall FCR was significantly better in birds fed on the mid-Fe diets with phytase supplementation.3. A significant improvement in ileal digestibility of N, P, Mg and Fe was observed in birds feed diets containing 60 mg Fe/kg, with significant interaction between Fe and phytase.4. Phytase improved the bone breaking strength when supplemented to low- or mid-Fe diets, compared to the non-supplemented diets. There was a significant Fe × phytase interaction effect. Tibia Fe content was higher in birds fed on phytase-free diets with high Fe but the reverse was the case when phytase was added and their interaction was significant. High dietary Fe significantly increased the accumulation of Fe in liver.5. Phytase improved Ca-Mg-ATPase, Ca-ATPase and Mg-ATPase activities in jejunum when supplemented to the diet containing 80 mg Fe/kg.6. This study indicates that high (100 mg/kg) dietary Fe inhibited phytase efficacy and subsequently reduced the overall performance and nutrient utilisation of broilers.

Tolerance to 1,25 dihydroxyvitamin D3 glycosides from Solanum glaucophyllum by the growing pig

Solanum glaucophyllum leaves contain high levels of glycosidically bound 1,25 dihydroxyvitamin D3, the most important vitamin D metabolite. The tolerance to this source was evaluated during six weeks with fifty weaned pigs fed increasing levels (0, 2.5, 5, 10 and 20μg 1,25(OH)2D3/kg diet). The diet contained, per kg, 9.7g Ca, 3.5g digestible P and 2000IU cholecalciferol. Ten additional pigs were fed a diet containing 1000IU cholecalciferol/kg, without 1,25(OH)2D3. Weekly plasma and final kidney, bone and urinary mineral contents, bone density and breaking strength served as indicators for possible adverse effects of the supplement. All animals grew well and remained clinically healthy. The measured parameters remained unchanged when 1000 replaced 2000IU cholecalciferol/kg and when 1,25(OH)2D3 was fed up to 10μg/kg. Twenty μg 1,25(OH)2D3 increased plasma Ca and decreased plasma P from the 2nd and the 4th experimental week onwards, respectively. Twenty μg 1,25(OH)2D3 increased final plasma Ca and 1,25(OH)2D3 and reduced final plasma P by respectively 19, 56 and 13%. Twenty μg 1,25(OH)2D3 also increased kidney Ca and urinary Ca by 43 and 69%, respectively, reduced bone breaking strength by 12% and tended to decrease bone ash by 3%. To conclude, 2000IU D3 was not beneficial compared to 1000IU cholecalciferol; up to 10μg 1,25(OH)2D3 per kg diet did not lead to observed adverse effects; 20μg 1,25(OH)2D3 altered the homeostatic regulation of Ca and P thus, may lead to first signs of possible adverse effects, such as soft tissue calcification.

Response to withdrawal of vitamin and trace mineral premixes from finisher diet in broiler chickens under the hot and humid tropical condition

This study was conducted to assess the effects of omitting vitamin (VIT) and trace mineral (TRM) premixes from the finisher diet on growth performance, antibody production against Newcastle disease (ND) vaccination, leg bone strength and incidence of foot pad dermatitis (FPD) in male and female broiler chickens. Birds were raised on floor pens in a naturally ventilated house using wood shavings as litter. Commencing from day 21, equal number of male and female birds were subjected to one of four VIT and TRM premixes withdrawal treatments as follows: (i) withdrawal from 21 to 42 days, (ii) withdrawal from 28 to 42 days, (iii) withdrawal from 35 to 42 days, and (iv) no withdrawal (control). In comparison to the control group, feed intake, body weights, feed conversion ratios and antibody responses to Newcastle disease vaccination were not affected by any of the supplement withdrawal treatment. Male birds had lower antibody production and higher bone-breaking strength as compared to their female counterparts. Irrespective of gender, withdrawal of VIT and TRM premixes from 21 to 42, and 28 to 42 days adversely affected bone-breaking strength. In conclusion, VIT and TRM premixes can be removed from the diet of male and female broiler chickens from 21 to 42 days without any adverse effects on growth performance, mortality, antibody response and incidence of foot pad dermatitis. However, bone-breaking strength was adversely affected by the withdrawal of VIT and TRM premixes for more than seven days.

Boron Supplementation Influences Bone Mineralization by Modulating Expression of Genes Regulating Calcium Utilization

The influence of dietary boron (B) supplementation on bone mineralization in rats with or without dietary calcium (Ca) restriction was studied in a feeding trial of 90d. Wister strain male rats (n=84; ∼34 wks of age) were divided into seven dietary groups (4 replicates of 3 each) namely, Normal-Ca (100%) basal diet alone (NC, control; 1.69 ppm B) or supplemented with B at 5 (NCB-5), 10 (NCB-10), 20 (NCB20) and 40 ppm (NCB-40) levels; low-Ca (50%) basal diet alone (LC) or supplemented with 40 ppm B (LCB-40). After 90d of experimental feeding, a 5d digestibility trial was conducted to estimate gut absorption of minerals. Eight rats from each group were sacrificed to collect blood for estimation of minerals, femur bone for assessment of minerals, bone breaking strength and radiography, and liver for appraisal of relative mRNA abundance of calmodulin (CAL), vitamin D binding protein (VDBP) and thyroid receptor binding protein (TRBP). Boron supplementation to Ca adequate diets improved (P<0.05) the gut absorption efficiency of Ca (at 5 and 10 ppm B) and Ca content in serum (at 20 at 40 ppm B). The Ca content in femur bone, its (bone) breaking strength and cortical index were observed to be lowest (P<0.05) in the LC group, and were improved (P<0.05) with B-supplementation (40 ppm). Supplementation of B improved (P<0.01) the relative mRNA expression levels for VDBP (at 10 ppm B) and CAL (at 10, 20 and 40 ppm B) in liver tissue as compared to control. The present study indicates a positive and supportive role of B in Ca utilization with both normal and restricted level of dietary Ca and bone mineralization which was mediated through modulation of Ca regulating genes.

Evaluation of the effects of gastrectomy on the development of metabolic bone disease

BackgroundMetabolic bone disease after gastrectomy is one of the complications leading to deterioration in quality of life. The exact mechanism of the metabolic bone disease remains unclear. To clarify the cause of metabolic bone disease after gastrectomy, we evaluated the associations between the method of gastrectomy and the development of metabolic bone disease in a rat model. MethodsRats were assigned to four groups as follows: (1) sham operation (control group); (2) resection of the glandular stomach with Billroth I reconstruction (RGBI group); (3) Roux-en-Y anastomosis preserving the secretory function of the whole stomach (PSRY group); and (4) total gastrectomy with Roux-en-Y reconstruction (TGRY group). In all groups, body weight, serum biochemistry (total protein, albumin, calcium, phosphorus, tartrate-resistant acid phosphatase, and bone alkaline phosphatase), bone density, and bone breaking strength were measured. ResultsBody weights and serum calcium levels were significantly lower in the three operation groups compared with the control group. Bone density was significantly lower in the PSRY and TGRY groups compared with the control group. Bone breaking strength was significantly lower in the three operation groups compared with the control group. ConclusionsSurgical methods led to metabolic bone disease. However, exclusion of the duodenum from food passage had major influence to reduction in bone density and breaking strength. A stomach-preserving procedure and physiological reconstruction which enable food passage through duodenum and proximal jejunum contribute to mitigation of metabolic bone disease.

Effect of dietary calcium level and source on mineral utilisation by piglets fed diets containing exogenous phytase

Calcium and phosphorus are essential minerals, closely linked in digestive processes and metabolism. With widespread use of low P diets containing exogenous phytase, the optimal dietary Ca level was verified. The 40-day study evaluated the effects of Ca level (4, 7 and 10g/kg diet) and Ca source (Ca from CaCO3 and from Lithothamnium calcareum) on mineral utilisation in 72 piglets (7.9±1.0kg BW) fed an exogenous phytase containing diet with 2.9g digestible P/kg. Measured parameters were growth performance, stomach mineral solubility, bone breaking strength and urinary, serum and bone mineral concentration. The apparent total tract digestibility of minerals was also assessed in the two diets with 7g Ca/kg, using 12 additional pigs. Regardless of Ca source, increasing dietary Ca impaired feed conversion ratio, increased urinary pH, increased serum and urinary Ca, decreased serum and urinary P, decreased serum Mg and increased urinary Mg, increased serum AP activity, decreased bone Mg increased bone Zn. Bone breaking strength was improved with 7 compared to 4g Ca/kg. Compared to CaCO3 , Ca from Lithothamnium calcareum increased serum Mg and with, 10g Ca/kg, it limited body weight gain. The dose response of Ca in a diet with 2.9g digestible P/kg and including exogenous phytase indicated that: (i) a low dietary Ca was beneficial for piglet growth, but was limiting the metabolic use of P; (ii) a high dietary Ca level impaired P utilisation; (iii) the optimal P utilisation and bone breaking strength was obtained with a dietary Ca-to-digestible P ratio of 2.1 to 2.4:1; (iv). Increasing dietary Ca reduced Mg utilisation, but not Zn status, when fed at adequate level. Finally, Ca from Lithothamnium calcareum had similar effects on Ca and P metabolism as CaCO3 , but impaired growth when fed at the highest inclusion level.

Response of broiler chickens to different levels of calcium, non-phytate phosphorus and phytase

ABSTRACT1. Five hundred and seventy six-d old Ross 308 broiler chicks (6 cages per diet, 8 birds per cage in 3 × 2 × 2 factorial arrangement) were fed on maize–soybean meal-based diets containing three concentrations of Ca (6, 8 or 10 g/kg), two concentrations of non-phytate phosphorus (NPP) (3 or 4 g/kg) and two levels of exogenous microbial phytase (0 or 500 FTU/kg) from d 0 to 35.2. Body weight (BW), feed intake (FI) and mortality records were collected. Two birds per replicate were killed at 24 d of age to obtain tibia samples.3. Increasing Ca level significantly reduced the FI and body weight gain (BWG) between hatch and 10 and 24 d, especially with the phytase-supplemented diets. However, phytase supplementation of the diet containing 4 g NPP/kg improved the FI and BWG at d 10 and 24. At d 24, phytase supplementation improved feed conversion ratio (FCR) of birds that consumed diets containing high NPP. The overall FCR was better in birds offered the phytase-supplemented, medium-Ca diet.4. There was a significant reduction in length, width and breaking strength of the tibia bone in birds fed on a diet with high Ca and low NPP. Phytase supplementation improved the tibia ash content and bone breaking strength of chicks fed on the diet containing 8 and 4 g/kg Ca and NPP, respectively. The Ca content of the tibia bone was low in birds fed on diets with 6 and 4 g/kg Ca and NPP, respectively, but this was counteracted by phytase supplementation.5. Birds fed on diets with 4 g/kg NPP had the best carcass percentage and parts yield. Phytase supplementation to high-Ca diets significantly reduced the carcass yield of birds.6. These results confirmed the detrimental effect of high dietary Ca on phytase activity and subsequent growth and bone development of birds, especially when NPP is in short supply.

Effects of early energy and protein restriction on growth performance, clinical blood parameters, carcass yield, and tibia parameters of broilers

This study was conducted to investigate the effects of dietary energy and protein dilution from age 8 to 14 d on growth performance, clinical blood parameters, carcass yield, and tibia parameters of broilers. Treatments were assigned in a completely randomized manner with factorial arrangement (4×4) including 4 levels of energy dilution and 4 levels of protein dilution. All birds were fed the same diet during the remaining period of time. The feeds were weighed every week, and the birds were weighed at 7, 14, and 42 d. At 14 d, blood samples were taken for clinical chemistry measurements, and 4 birds from each replicate were sacrificed to measure carcass yield and tibia parameters at 42 d. From 8 to 14 d, average daily feed intake (ADFI) of the 20% protein dilution group increased significantly compared with that of the 10% protein dilution group (P<0.05). The feed conversion ratio (FCR) of the group with 30% protein dilution and 15% energy dilution creased the most among all treatment groups. From 15 to 42 d, the ADFI and FCR of the 20% protein dilution group were greater than those of the 0 and 10% protein dilution groups (P<0.05), and the FCR of the 15% energy dilution group increased significantly (P<0.05). At 42 d, body weight (BW) of the 15% energy dilution group was less than that of the other groups (P<0.05). Significant interactions were observed in ADFI, FCR, and BW at 42 d of age between energy dilution and protein dilution (P<0.05). At 14 d, serum total protein levels of birds in the 20 and 30% protein dilution groups decreased significantly compared to that of the 10% protein dilution group (P<0.05). Blood urea nitrogen concentration of birds in the 20 and 30% protein dilution groups decreased significantly compared with those in 0 and 10% protein dilution groups (P<0.05). Triacylglycerol concentration of birds in the 20% protein and 10% energy dilution groups decreased significantly compared with that of the 0 dilution group (P<0.05). The carcass yields were unaffected by dilution of energy and protein (P>0.05). The bone breaking strength of the 15% energy dilution group decreased significantly compared with that of the 5% energy dilution group (P<0.05). This study suggested that dietary protein and energy reduced 10% from 8 to 14 d of age can not affect the growth performance and other indexes in broilers.

Effects on Productive Performance, Tibia Calcium and Phosphorous Retention, and Liver Enzymes Activity of Acidified and Alkalinized Diets in Broiler Chicken

Abstract A 35-day experiment was carried out to study the effects of acidified and alkalinized diets on zootechnical indices, tibial calcium and phosphorous retention, bone mineralization and liver enzymes activity using 250 Ross 308 male broiler chicks. Five treatments consisting of a control diet (CD), CD acidified using 10, 20 and 30 g/kg citric acid (CA) and CD alkalinized with Ca (OH)2 (8.9 g/kg in growth period and 8.6 g/kg in finisher period) were examined in 5 replicates of 10 birds each from day 7 up to day 42 of age. Inclusion of 30 g/kg CA significantly increased body weight, average daily gain (ADG), average daily feed intake (ADFI), feed efficiency, tibia ash, tibia Ca content, at day 42 of age (P&lt;0.05). Serum alkaline phosphatase and lactate dehydrogenase activities were elevated in the birds fed with the 30 g/kg CA-treated diet at day 42 of age (P&lt;0.05). Alkalinized diet significantly reduced ADFI, tibia ash, tibial P and Ca contents, bone breaking strength and plasma Ca concentration (P&lt;0.05). It was concluded that the diet acidified with 30 g/kg CA promoted productive performance and tibia mineralization in broiler chicken. Alkalinized diet suppressed growth performance of the birds perhaps through disrupted mineral absorption and altered liver enzymes activity.

Hulled and hull-less barley grains with the genetic trait for low-phytic acid increased the apparent total-tract digestibility of phosphorus and calcium in diets for young swine.

A 35-d experiment was conducted using 63 crossbred pigs (35 barrows and 28 gilts) with an initial average BW of 7.0 kg and age of 28 d to evaluate the efficacy of the low-phytic acid (LPA) genetic trait in hulled or hull-less barley in isocaloric diets. Hulled barleys were the normal barley (NB) cultivar Harrington and the near-isogenic LPA mutant 955 (M955) with P availabilities of 36 and 95%, respectively. Hull-less lines were produced by crossing NB and the LPA mutant 422 line with a hull-less line, producing hull-less NB (HNB) and hull-less mutant 422 (HM422) with P availabilities of 41 and 66%, respectively. Pigs were in individual metabolism cages or pens for Phase 1 (d 0 to 14) and Phase 2 (d 14 to 35). Diets defined as NB, HNB, HM422, or M955 with no added inorganic P (iP) had available P (aP) concentrations of 0.27, 0.28, 0.35, and 0.40% for Phase 1 and 0.15, 0.17, 0.23, and 0.31% for Phase 2, respectively. Only diet M955 was adequate in aP. Therefore, iP was added to the P-deficient diets to make diets NB + iP, HNB + iP, and HM422 + iP with aP equal to that in diet M955. Overall (d 0 to 35), ADG and G:F were greater ( < 0.01) for pigs fed diet M955 or the diets with added iP than for pigs fed the NB diet. Serum tartrate-resistant acid phosphatase activity on d 34 was greater ( < 0.01) for pigs fed the NB or HNB diets than for pigs fed the other diets. Bone breaking strength and P absorption (g/d) were greater ( < 0.01) for pigs fed diet M955 or the diets with iP than for pigs fed the NB or HNB diets. Pigs fed diet M955 absorbed greater ( < 0.01) percentages of P and Ca and had less ( < 0.01) fecal excretion of P (g/d and %) and Ca (%) than pigs fed the other diets. In conclusion, the LPA genetic trait was effective in hulled and hull-less barley in isocaloric diets fed to young pigs. Pigs fed the diet with LPA M955 consumed 31% less P and excreted 78% less fecal P and 30% less fecal Ca than pigs fed the diet with NB + iP that was equal to diet M955 in aP. Therefore, LPA barley, especially M955 with 95% aP, will reduce the use of iP in swine diets, reduce P pollution from swine manure, and support the goal of achieving global P sustainability.