Bone mineral density: review

Decreased eggshell strength caused by impairment of uterine calcium transport coincide with higher bone minerals and quality in aged laying hens

BACKGROUND

Deteriorations in eggshell and bone quality are major challenges in aged laying hens. This study compared the differences of eggshell quality, bone parameters and their correlations as well as uterine physiological characteristics and the bone remodeling processes of hens laying eggs of different eggshell breaking strength to explore the mechanism of eggshell and bone quality reduction and their interaction. A total of 240 74-week-old Hy-line Brown laying hens were selected and allocated to a high (HBS, 44.83 ± 1.31 N) or low (LBS, 24.43 ± 0.57 N) eggshell breaking strength group.

RESULTS

A decreased thickness, weight and weight ratio of eggshells were observed in the LBS, accompanied with ultrastructural deterioration and total Ca reduction. Bone quality was negatively correlated with eggshell quality, marked with enhanced structures and increased components in the LBS. In the LBS, the mammillary knobs and effective layer grew slowly. At the initiation stage of eggshell calcification, a total of 130 differentially expressed genes (DEGs, 122 upregulated and 8 downregulated) were identified in the uterus of hens in the LBS relative to those in the HBS. These DEGs were relevant to apoptosis due to the cellular Ca overload. Higher values of p62 protein level, caspase-8 activity, Bax protein expression and lower values of Bcl protein expression and Bcl/Bax ratio were seen in the LBS. TUNEL assay and hematoxylin-eosin staining showed a significant increase in TUNEL-positive cells and tissue damages in the uterus of the LBS. Although few DEGs were identified at the growth stage, similar uterine tissue damages were also observed in the LBS. The expressions of runt-related transcription factor 2 and osteocalcin were upregulated in humeri of the LBS. Enlarged diameter and more structural damages of endocortical bones and decreased ash were observed in femurs of the HBS.

CONCLUSION

The lower eggshell breaking strength may be attributed to a declined Ca transport due to uterine tissue damages, which could affect eggshell calcification and lead to a weak ultrastructure. Impaired uterine Ca transport may result in reduced femoral bone resorption and increased humeral bone formation to maintain a higher mineral and bone quality in the LBS.

Dietary protein levels during 12 to 26 wk improve the growth performance, bone quality, and testosterone in Pearl Gray male guinea fowl (Numida meleagris)

Guinea fowl (Numida meleagris), although native to Africa and despite its many potentials, does not represent the dominant species on the continent because of its seasonal reproductive nature and high keets mortality. This study was conducted to assess the effect of crude protein levels on growth performance, bone characteristics and reproductive activity of Pearl Gray male breeder guinea fowl from 12 to 26 wk of age. A total of 120 twelve-wk-old guinea fowls were randomly allotted to 3 dietary treatments with 8 replicates each and 5 birds per replicate using a completely randomized design. The dietary treatments comprised low level (LL), normal level (NL), and high level (HL) with diets respectively containing 15, 17, and 19% crude protein (CP). The results showed that guinea fowl in the HL treatment had a significantly lower feed conversion ratio (P = 0.008) than those in the other treatments. The birds fed the HL diet had significantly higher concentrations of testosterone (P < 0.05) than in the other treatments. High levels of calcium and phosphorus were observed in the femur of the HL group relative to the LL group. The birds in the LL treatment had a significantly higher (P = 0.007) femur robusticity index than those in the HL treatment. In conclusion, feeding 19% crude protein to Pearl Gray male guinea fowl from 12 to 26 wk of age improves growth performance, the density and strength of the femur and tibia and the reproductive tract. The CP level for the best performance of male guinea fowl from 12 to 26 wk of age is 19%.

Phase angle and body composition: A scoping review

The aim of the study was to map evidence on the association between phase angle (PhA) and body composition in populations healthy and clinical populations). A systematic search for information regarding the topic was conducted in nine electronic databases (CINAHL, LILACS, PubMed, SciELO, Scopus, SPORTDiscus, Science Direct, MEDLINE and Web of Science) between October and November 2021. Studies with different designs, which allowed extracting information about the relationship between PhA and body composition (body cell mass [BCM], muscle tissue, bone mineral content, lean mass, total fat mass, visceral fat, and lean soft tissue mass [LSTM]) were included. Of the total of 11,913 initially identified studies, 59 were included after reading titles, abstracts, full texts and references. Most studies (40.67%; n = 24) presented data from Brazilian samples. With regard to the design of studies, 15 (25.42%) had longitudinal design. The age group of studies was wide, with studies involved 3-year-old children and 88-year-old adults. Body fat mass was evaluated by 31 studies (52.54%) in which 11 observed inverse relationships, nine studies showed direct relationships and 11 observed no relationship. Regarding lean mass, muscle mass, and fat-free mass components, most studies observed direct relationship with PhA (n = 37; 86.04%). It could be concluded that the phase angle was directly associated with lean mass and muscle mass in different age groups (children, adolescents, adults and older adults) and in people with different health diagnoses (HIV, cancer, hemodialysis, sarcopenia and without the diagnosis of diseases). Regarding body fat and the other investigated components, there is not enough evidence to establish the direction of associations.

Assessing Bone Health Status and Eggshell Quality of Laying Hens at the End of a Production Cycle in Response to Inclusion of a Hybrid Rye to a Wheat-Corn Diet

The objective of this study was to evaluate whether there are negative effects of the partial replacement of white corn with rye along with xylanase supplementation on overall bone quality, eggshell mineralization, and mechanical strength in laying hens. From the 26th week of life, ISA Brown laying hens were fed either a wheat-corn diet or a diet containing 25% rye, with or without xylanase. The experimental period lasted for 25 weeks, until birds reached their 50th week of age, after which bone and eggshell quality indices were assessed. Eggshell thickness and eggshell Ca content of eggs from rye-fed hens were improved by xylanase supplementation. No differences in the mechanical properties of the eggshells were observed between treatments, except for the diet-dependent changes in egg deformation. Rye inclusion had no effect on the mechanical properties of bone. Xylanase supplementation, irrespective of the diet, had a positive effect on bone strength and increased tibia Ca content, as well as the content of several microelements. Hence, hybrid rye combined with wheat can replace 25% of corn in layer diets without compromising shell quality or bone mineral content. Xylanase supplementation in these diets is recommended since its inclusion improves both bone strength and quality.

The Effects of Providing Outdoor Access to Broilers in the Tropics on Their Behaviour and Stress Responses

Simple Summary

The effects of outdoor access for broilers have been tested under temperate conditions, where free-range systems have begun to be widely used. However, under tropical conditions, where the birds may be heat-stressed outside, the benefits of providing a free-range area may be less evident. We compared whether access to an outdoor area improved behavior and several physiological welfare indicators of broilers at two stocking densities in a tropical environment. There were no major effects of outdoor access on broiler behavior, except that resting was reduced by providing outdoor access to older birds and those at low stocking densities inside. However, outdoor access increased heterophil numbers in summer, but not in winter, which may indicate heat stress. We concluded that the effects of outdoor access on the welfare of broilers in the tropics are dependent on season and stocking density.

Abstract

The effects of outdoor access, stocking density, and age on broiler behavior, stress, and health indicators in a tropical climate were assessed over two seasons, winter and summer. Two hundred and forty Cobb500 male chickens were allocated to one of four treatments, with six replicates of ten birds in each: low stocking density indoors with outdoor access (LO); high stocking density indoors with outdoor access (HO); low stocking density indoors without outdoor access (LI); and high stocking density indoors without outdoor access (HI). Scan sampling was used to record their behavior both indoors and outdoors. At 28 and 42 days old, blood samples were obtained to determine the heterophil to lymphocyte (H/L) ratio. At 42 days old, chickens were culled and inspected for footpad dermatitis (FPD), and bone quality was examined. Their spleens and bursas of Fabricius were collected and weighed, relative to carcass weight (RW). A factorial analysis was used to test the effects of season (winter or summer), outdoor access (with or without), stocking density (low: 5 animals/m² or high: 10 animals/m²), and age (28 or 42 days) on the behavior and stress and health indicators. There were no major effects of providing outdoor access on behavior, except that resting was reduced by providing outdoor access to older birds and those at low stocking densities inside. Resting was also greater in indoor and high-density treatments during winter. The bursa of Fabricius was heavier in summer in outdoor birds. The tibia bones were shorter in the outdoor birds. Heterophil numbers were greater in the outdoor treatments in summer but not in winter. These results indicate that outdoor access can increase activity in some situations, and potentially increase bone strength, but it may also increase the risk of stress, particularly heat stress in summer.

Efficacy of three heat-stable microbial phytases on growth performance and bone development and strength of broilers fed diets deficient in available phosphorus

This study evaluated the response of broilers to either of three phytase enzymes in a P-deficient diet. A total of 2340 as-hatched Cobb500 chicks were allocated to nine treatments, each with 13 replicate pens. Starter and finisher diets consisted of a positive control (PC), negative control 1 and 2 (NC1, NC2). The PC, NC1 and NC2 diets had Ca:avP ratios of 0.50, 0.33 and 0.43 in the starter feed; and 0.46, 0.22 and 0.35 in the finisher feed; NC1 diets were then supplemented with Phytaverse, Quantum Blue and Axtra-PHY at 500 and 1000 FTU/kg. Enzyme type had a significant effect on body weight gain, feed conversion ratio (FCR) and production efficiency factor (PEF) during the 0-7 d period. Interactions between enzyme type and inclusion levels had a significant effect on feed intake (FI) at 1-21 d (P =0.02) and 1-35 d (P =0.031) age. While FI decreased as Axtra-PHY inclusion levels increased from 500 to 1000 FTU/kg feed, FI increased in birds supplemented with Quantum Blue, but with no effects on Phytaverse supplemented birds. Increasing enzyme dose to 1000 FTU/kg feed improved bone breaking strength but did not affect growth performance, tibia ash, Ca or P concentration of the birds.

A Comparison of Morphometric Indices, Mineralization Level of Long Bones and Selected Blood Parameters in Hens of Three Breeds

The aim of the study was to compare morphometric indices and the mineralization level of humerus, femur and tibia in Leghorn (H-22), Sussex (S-66) and Rhode Island Red (R-11) hens at different age (weeks 6, 16, 45 and 64), as well as some blood parameters. The material for the experiment was one-day old chicks of breeds: Leghorn (H-22), Sussex (S-66) and Rhode Island Red – RIR (R-11), which were separated into three groups. At 6, 16, 45 and 64 weeks of the study, 10 birds selected from each group were weighed, slaughtered, and their right femurs, tibiae and humeri were dissected. After removing soft tissues, the bones were weighed and measured for length, diameter, and the Seedor index (SI) was calculated. The bones were analysed for the content of calcium (Ca), phosphorus (P) and crude ash (CA). At 64 weeks, blood was collected from the hens and analysed for the concentration of Ca, P, pyridinoline and deoxypyridinoline. The study showed that hen breed had an effect mostly on morphometric indices of the bones such as bone weight and diameter, and the Seedor index (SI), while the age of birds had an effect on the bone mineralization level up to 45 weeks of age. The bone mineralization did not decrease in the studied breeds of hens at the end of the laying period. It was also found that heavier birds (RIR) had greater diameter bones and a higher SI, but the content of ash and minerals in the bones of that breed was generally similar to the Leghorn and Sussex hens. RIR hens exhibited higher plasma phosphorus concentration compared to Sussex hens. This may suggest that RIR birds have a slightly stronger bone system compared to Leghorn and Sussex hens.

Evaluating the physical condition of Hyla japonica using radiographic techniques

Amphibian populations are declining throughout the world, which has negatively impacted various organisms and ecosystems. The goal of this study was to obtain a better understanding of the physiological status and condition of individuals in amphibians is needed to preserve these groups. We used radiography to assess physical conditions in Hyla japonica frogs, which are widely distributed in East Asia. Bone images were examined to determine fractures and metabolic bone disease of frogs in a wild population. The bone-mineral density (BMD), stable nitrogen isotope ratio (δ¹⁵N), and physical conditions (body length, age, and body weight) and body compositions (fat mass and lean mass) were measured to identify changes correlating with the food-intake status. To analyze the physiological and morphological effects of predation pressure in H. japonica, we compared the BMD, food-intake status, physical conditions, body compositions and skeletal shape in H. japonica between populations with Lithobates catesbeianus (paddy fields with bullfrogs; PB) and without L. catesbeianus (no bullfrogs; NB). Only five of 101 H. japonica frogs had fractures, and no bone disease due to malnutrition was found. The food-intake status correlated with the BMD, but not to the other physical conditions and body compositions measured. Similarly, the BMD and δ¹⁵N of the NB group were higher than those of the PB group, but the other physical conditions and body compositions were not different. The skeletal shapes of the head and lower body were not significantly different between the two groups. Our findings revealed that the BMD can be used to determine the food-intake status and be changed in by predation pressure. We suggest using the BMD of anurans to estimate physiological changes that occur in response to the habitat or biological interactions.

Determination of basal bone mineral density in the femur bones of male and female Wistar rats

Changes in bone mineral content of calcium (Ca), phosphorous (P), magnesium and potassium for male and female Wistar rats during their development from 3 weeks old to adulthood (27 weeks old) were measured. Bone mineral content was related to areal bone mineral density (BMD) which was measured in vivo at the femoral neck using a calibrated X-ray transmission system to obtain basal curves as a function of the age of the specimen. Diagnostic curves were built to determine low BMD (osteopaenia) and osteoporosis in female rats fed a Ca-depleted diet (50%) based on the obtained data and the criteria established by the World Health Organization. Bone mineral content is directly related to sex and age, but P did not change throughout the experimental period. P content did not exhibit significant changes with growing, while Ca was greatest in male rats, producing significant differences in the Ca:P ratio. Male rats reach the Ca:P ratio peak before female rats. However, areal BMD does not follow the same trend. On the other hand, osteoporosis produced a 45% decrease in this parameter for young and mature adults. These results make Z-score values available to diagnose bone-mass losses and hence the possibility of improving the conditions of non-contact measurement of BMD in vivo. This technique can be used for future experiments with Wistar rats.

Calcium and available phosphorus requirements of Japanese quails in early egg-laying stage

An experiment was conducted to estimate the nutritional requirements of calcium (Ca) and available phosphorus (aP) for Japanese quails (Coturnix coturnix japonica) in the egg-laying stage (64–168 D). The experiment was an entirely randomized design, in a factorial scheme (Ca = 1.70, 2.40, 3.10, and 3.80% and aP = 0.15, 0.30, 0.45, and 0.60%), with 3 replicates and 10 quails per experimental unit. No interactions were found for quail body weight and daily feed intake (DFI) (P > 0.05). However, body weight decreased linearly (P < 0.05) as the levels of Ca increased, whereas DFI exhibited a quadratic effect (P < 0.05) for both Ca and aP. The lowest values of DFI were estimated in 2.79 and 0.36% for Ca and aP, respectively. Egg production, egg mass, and feed conversion ratio per egg dozen presented significant interaction in which all of them had a quadratic effect (P < 0.05), with estimations for maximum yield in feed containing 2.74, 2.71, 2.75, and 2.74% Ca and 0.40, 0.39, 0.39, and 0.40% aP. The concentration of Ca in the eggshell increased linearly as per the levels of Ca studied, having a quadratic effect for aP levels, with a maximum point of 0.44%. In relation to the bone parameters, there was a linear interaction for Ca and aP in bone density and bone resistance (BR) of the femur, with a quadratic effect in BD estimating 2.84 and 0.50% for Ca and aP, respectively. In BR, the estimation was 3.27% Ca, with linear increase for aP. The BR of the tibiotarso increased linearly as per the Ca levels, obtaining the same Ca concentration response in this bone. As conclusion, when considering the estimations obtained through overlapped contour plots, the best responses to the effects of Ca and aP on productive characteristics were estimated at 2.68% Ca and 0.38% aP to produce feed for egg-laying Japanese quails.

Long term effect of dietary lipid saturation on eggshell quality and bone characteristics of laying hens

This study investigated the long-term effect of dietary fatty acid saturation on eggshell quality and bone characteristics of laying hens at end of lay. Five isoenergetic (3,011.5 kcal AME/kg DM) and isonitrogenous (169 g CP/kg DM) diets were formulated using different lipid sources at a constant 30 g/kg inclusion level. The control, polyunsaturated omega-3 (PUFA n-3), polyunsaturated omega-6 (PUFA n-6), monounsaturated omega-9 (MUFA n-9), and saturated fatty acid (SFA) diets consisted of linseed- and fish oil (50:50 blend), fish oil, sunflower oil, high oleic acid sunflower oil, and tallow, respectively. A total of 200 individually caged Hy-Line Silver-Brown hens (20 wk of age) were randomly allocated to the 5 treatments (n = 40 replicates/treatment) and received the experimental diets for 54 wk. During weeks 58, 62, 66, 70, and 74 of age (end-of-lay period), 20 eggs/treatment per day (n = 140 eggs/treatment per week) were selected for determining eggshell quality traits. At 74 wk of age, 10 birds per treatment (n = 10 birds/treatment) were randomly selected for the determination of bone quality characteristics. Data were statistically analyzed (P < 0.05) using a fully randomized 1-way ANOVA. Dietary treatment had no effect (P > 0.05) on eggshell quality traits. The MUFA n-9 treatment with the highest unsaturated to SFA ratio (UFA: SFA) resulted in a higher (P < 0.05) femur weight (10.34 g) as well as femur- (52.99%) and tibia ash (51.07%) content than the SFA treatment. Also, the PUFA n-3 diet resulted in a higher (P < 0.05) femur weight (10.21 g), femur ash (51.82%), and percentage femur (0.57%) compared to the SFA diet. Results suggested that prolonged feeding of diets varying in FA profile had no negative effect on eggshell quality, whereas UFA: SFA and long-chain n-3 PUFA affected the bone quality (especially the femur) of hens at the end of lay.

Combination of phytase and citric acid, but not phytase alone, ensures regular rates of growth and bone mineralization in quails under severe phosphorus restriction

An experiment was conducted to evaluate the effects of phytase (PHY), alone or in combination with citric acid (CA), on growing Japanese quails under moderate and severe phosphorus (P) restriction. For this, 504 one-day-old female quails were distributed in a completely randomised design with seven treatments and six replications. Treatments consisted of the following diets: (a) positive control (PC): formulated according to quails nutritional requirements; (b) negative control 40% (NC₄₀ ): PC with 40% less aP; (c) NC₄₀ +PHY; (d) NC₄₀ +PHY+CA; (e) negative control 65% (NC₆₅ ): PC with 65% less aP; (f) NC₆₅ +PHY; (g) NC₆₅ +PHY+CA. Phytase and CA were included at 300 FTU/kg and 40 g/kg, respectively. Performance, bone mineralization and plasma mineral concentration were evaluated at day 35; calcium (Ca) and P metabolism, between days 36 and 39. No significant differences in performance, plasma Ca and P were detected between quails fed PC or NC₄₀ ; however, NC₄₀ decreased tibia ash (p < 0.01). Treatment NC₆₅ impaired daily weight gain (p = 0.01), tibia ash (p < 0.01), and tibia optical densitometry (p = 0.03), as well as modified plasma Ca (p < 0.01) and P (p = 0.03) concentrations when compared to PC. Both NC₄₀ and NC₆₅ reduced P excretion (p < 0.01). Phytase alone restored tibia ash of NC₄₀ quails to regular rates. Nevertheless, only PHY and CA combined returned plasma P, tibia ash, tibia optical densitometry, and daily weight gain of quails fed NC₆₅ to similar values as those observed in PC. In conclusion, PHY alone suppresses the negative effects of moderate P restriction in growing Japanese quails, but fails in this task under severe P restriction. In such a situation, only the combination of PHY and CA ensures regular rates of growth and bone mineralization. This concept should be better explored by producers in order to take full advantage of the reduction in P excretion achieved by lowering dietary P concentrations.

Novel Formulated Fortified Blended Foods Result in Improved Protein Efficiency and Hepatic Iron Concentrations Compared with Corn-Soy Blend Plus in Broiler Chickens

BACKGROUND

Corn- and soybean-based fortified blended foods (FBFs) have been the primary food aid product provided by the United States. Sorghum and cowpea have been suggested as alternative FBF commodities because they are drought-tolerant, grown in food aid-receiving areas, and not genetically modified. Extrusion processing has also been suggested to improve the quality of these FBFs.

OBJECTIVES

The aim of this study was to determine the protein quality and iron and vitamin A bioavailability of novel FBFs in broiler chickens.

METHODS

Whey protein concentrate (WPC)-containing FBFs corn-soy blend 14, sorghum-soy, and sorghum-cowpea (SC); a soy protein isolate (SPI)-containing SC FBF (SC+SPI); 2 reformulated, overprocessed SC FBFs (O-SC+WPC, O-SC+SPI); and a nonextruded WPC-containing SC FBF were developed. Nonextruded corn-soy blend plus (CSB+), a currently used FBF, and a gamebird starter/grower diet were used as comparison diets. In the prepared FBF study, 9 groups of 8-d-old broiler chicks (n = 10) consumed prepared FBFs for 21 d. In the dry study, 8 groups of 4-d-old broiler chicks (n = 24; control: n = 23) consumed dry FBFs for 14 d. Results were analyzed by 1-factor ANOVA with least-significant-difference test.

RESULTS

In the prepared study, novel formulated FBFs significantly increased caloric and protein efficiency and nonsignificantly increased body weight gain, despite similar food intake compared with CSB+. In the dry study, novel formulated FBFs, except for O-SC+SPI, significantly increased food intake, caloric efficiency, and protein efficiency and nonsignificantly increased body-weight gain compared with CSB+. Novel formulated FBFs nonsignificantly and significantly increased hepatic iron concentrations compared with all FBFs in the prepared and dry studies, respectively.

CONCLUSION

Novel formulated FBFs, apart from O-SC+SPI, resulted in improved protein efficiencies and hepatic iron concentrations compared with CSB+, suggesting that they are of higher nutritional quality.

Phenamil, an amiloride derivative, restricts long bone growth and alters keeled-sternum bone architecture in growing chickens

"Broiler-type" chickens are fast-grow-ing, heavy-bodied birds with high demands on bone quality. Phenamil increased mineralization in cultured murine mesenchymal stem cells. Phenamil effects were tested in 2 groups of weight and gender matched day-old broiler chickens (n = 13). Oral administration of 30 mg phenamil/kg body weight d 1 to 13 reduced growth of chicks d 5 to 14 (P = 0.002); with phenamil-treated (PT) chick body weight being 84% of vehicle-treated (VT) chicks' body weight on d 14. Tissues collected on d 15 showed that femur lengths and widths did not differ, but tibias from PT chicks were 6% shorter (P = 0.002) and 13% narrower (P = 0.012) with 18% thinner tibial cross-sections (P < 0.008) than in VT chicks. Angles of the caudal aspect of the anterior surface of keeled-sternums were 166° in PT chicks, flatter than the 148° found in VT chicks (P = 0.000). Total mineral content of both tibia and femur were lower in PT chicks (P = 0.005 for both). Bone Ca, P, and Mg (ppm) in ash were similar, but Ca:P was lower (1.70 vs 1.75) in PT versus VT chicks (P < 0.05). Osteocalcin was ∼20% lower (P = 0.020), PINP was ∼45% higher (P = 0.000) in PT chicks. Carboxy-terminal telopeptide type I collagen (ICTP) and cross-linked N-telopeptide of type I collagen (NTX1) were similar in the 2 groups. Phenamil had unexpected and detrimental effects on bone formation in growing broiler chicks, reducing linear skeletal growth and markedly changing bone architecture.

Matriz porosa do BV60S no tratamento de defeitos ósseos críticosem rádios de cães

O objetivo deste estudo foi avaliar o efeito da matriz porosa do biovidro de composição molar 60% SiO2 - 36% CaO - 4% P2O5 (BV60S) no tratamento de defeitos ósseos críticos de cães. Foram utilizados 20 cães, machos, sem raça definida, com dois anos e massa corporal média de 25kg. Foram constituídos três grupos experimentais: defeitos ósseos preenchidos com BV60S (BV), com osso autógeno (C+) e defeitos não preenchidos (C-). A regeneração óssea foi avaliada por meio de exames radiográficos, densitométricos e histomorfométricos ao longo de 90 dias. A matriz do BV60S mostrou rápida reabsorção com redução média de 12,62% a cada 15 dias. A regeneração foi completa no grupo C+ e incompleta nos grupos BV e C-, aos 90 dias. A área de neoformação óssea foi semelhante entre os grupos BV e C-, em todos os tempos estudados. Conclui-se que a matriz porosa do BV60S possui rápida reabsorção, não sendo eficiente no tratamento de defeitos ósseos críticos em rádios de cães.

Densitometric and biochemical values of broiler tibias at different ages

The objective of this experiment was to determine the normal values of bone radiographic density (BRD) by using the optical densitometry in radiographic images and the biochemical values represented by serum calcium, ash percentage, and minerals (calcium, phosphorus, and magnesium) from tibia ash of Cobb broilers at 8, 22, and 43 d of age. A total of 14 broilers were used for densitometric analysis, and 15 were used for biochemical dosages. The BRD values increased (P < 0.05) with age and in all tibia regions (proximal epiphysis, diaphysis, and distal epiphysis), concluding that growth was a determinative factor for bone performance, demanding a higher BRD during broiler development. Tibia proximal epiphysis presented higher BRD values in relation to the other bone regions (P < 0.05), as a result of a possible biomechanical adaptation to ligaments and tension of the muscle tendons at this region, allowing the support of the muscle mass increase. The serum calcium values were kept constant, as a result of the appropriate nutritional levels of the diet that supported the animal homeostasis. The bone ash and mineral percentage increased (P < 0.05) at 22 d of age, due to the higher mineral requirement in this age. The correlation between bone densitometry and the invasive techniques showed that the bone densitometry can substitute the determination of mineral percentage in the ash. This experiment presented normal values of the noninvasive and invasive methods more used in aviculture, allowing us to compare, subsequently, pathological and physiological values or results of broilers fed with different diets.