Boron Supplementation Promotes Osteogenesis of Tibia by Regulating the Bone Morphogenetic Protein-2 Expression in African Ostrich Chicks.

The present study aimed to explore the effects of supplemental boron on osteogenesis of tibia and to investigate the possible relationship between additional boron and the expression of bone morphogenetic protein-2 (BMP-2) in tibia of ostrich chicks. Therefore, forty-eight African ostrich chicks (15 days old) were supplemented with 0 mg/L, 40 mg/L, 80 mg/L, 160 mg/L, 320 mg/L, and 640 mg/L of boron in drinking water for 75 days. The paraffin sections of tibia used to measure histomorphometric parameters by hematoxylin and eosin (HE) staining, Masson's staining, and immunohistochemistry (IHC). Enzyme-linked immunosorbent assay was performed to assess the level of BMP-2, osteocalcin (BGP), glucocorticoids (GCs), osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-B ligand (RANKL) in serum. TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) technique was performed to detect the cell apoptosis. The results indicated that low dose of supplemental boron (40 mg/L-160 mg/L) in drinking water promotes bone development by increasing the mature ossein. The expression of BMP2 on 45 days was higher than 90 days. Serum level of BMP-2, BGP, and GCs changed significantly in groups with low dosage of boron, and OPG/RANKL ratio was upregulated from 0 to 160 mg/L. Cell apoptosis was least in 40 mg/L and 160 mg/L groups. Taken together, low dose of boron supplemented in drinking water could promote osteogenesis and growth and development of tibia by regulating the expression and secretion of BMP-2 and providing a dynamically balanced environment for tibia growth, development, and reconstruction by regulating the concentrations of BGP, GCs, and OPG/RANKL ratio in serum.

Boron Affects the Development of the Kidney Through Modulation of Apoptosis, Antioxidant Capacity, and Nrf2 Pathway in the African Ostrich Chicks.

The nuclear-related factor 2 (Nrf2) pathway is the most important mechanism in antioxidant capacity, which regulates the cell's redox homeostasis. In addition, Nrf2 pathway also can inhibit cell apoptosis. The mechanism of boron actions on various organs is well documented. But, it is not known whether boron can also regulate the Nrf2 pathway in the kidneys. Therefore, in this research, the actions of boron on the kidneys of ostrich chicks, especially the antioxidant effects, have been studied. The ostrich chicks were divided into six groups and supplemented with boric acid (BA) (source of boron) in the drinking water (0, 40, 80, 160, 320, 640 mg respectively) to examine apoptotic, antioxidant, biochemical, and histochemical alterations induced by boron administration in the ostrich chick's kidney. The cellular apoptosis was assessed by terminal deoxynucleotidyl transferase dUTP Nick-End Labeling (TUNEL) assay. The relative antioxidant enzymes (T-AOC, MDA, GSH-Px, SOD, GR, CAT) and biochemical indices (ALT, AST, ALP, CK, LDH, BUN, CREA, UA) in the kidney were determined by spectrophotometric method. The expression of three important genes in the antioxidant pathway (Nrf2, HO-1, GCLc) was measured by quantitative real-time PCR (qPCR), and the localization of key regulator Nrf2 was examined by immunohistochemistry (IHC) method. Western blotting was also performed to further validate our results. Our results revealed that low doses of boron (up to 160 mg) had positive effect, while high doses (especially 640 mg) caused negative effect on the development of the kidney. The cellular apoptosis was in a biphasic manner by altering the boron quantities. The low doses regulate the oxidative and enzyme activity in the kidney. The IHC and western blot showed maximum localization of Nrf2 in 80 mg/L BA dose group. Furthermore, supplementation of boron at low doses upregulated the expression of genes involved in the antioxidant pathway. Taken together, the study demonstrated that low levels of boron (up to 160 mg) inhibited the cell apoptosis, regulate the enzyme activity, and improved the antioxidant system, thus may encourage the development of the ostrich chick's kidney, while a high amount of boron especially 640 mg/L promoted cell apoptosis and reduced the antioxidant capacity, thus caused negative effect to the ostrich chick's kidney.

Developmental morphology study on the stomach of African ostrich chicks.

This study investigates the developmental morphology changes on the proventriculus and gizzard of African ostrich chicks using gross anatomy, and light and transmission electronic microscopy. The body weight; the weight of the proventriculus and gizzard; the thickness of simple tubular glands, muscularis mucosae, compound tubular glands, and muscular layer of the proventriculus; and the thickness of the gizzard glands and muscularis mucosae were measured on postnatal d one, 45, 90, and 334. Under transmission electronic microscopy, the oxynticopeptic cells, mucous cells, and endocrine cells were observed in the proventriculus on postnatal d one, 45, and 90. Our results revealed that the weights of the proventriculus and gizzard (relative to the body weight) both peaked on d 90, respectively, and declined thereafter. The thicknesses of the simple tubular glands, muscularis mucosae, compound tubular glands, muscular layer of the proventriculus, and gizzard glands increased with increasing bird age. However, the thickness of the muscularis mucosae in the gizzard peaked on d 90 and gradually decreased thereafter. The result of transmission electron microscopy revealed that the glands in the submucosa layer of the proventriculus did not differ from other cell types, aside from an increase in cell diameter and an increase in cytoplasmic content. A significant increase in the number of mitochondria and smooth endoplasmic reticulum was noted, as well as an in granules secreted by endocrine cells. Therefore, to improve brood rates of reared African ostrich chicks, feed management ought to be enhanced between postnatal d one and day 90.

Effects of supplemental boron on growth performance and meat quality in African ostrich chicks.

To investigate the effects of boron on growth performance and meat quality, 10-day-old Africa ostrich chicks were randomly divided into 6 groups with 6 replicates in each group. For 80 days, birds in the treatments were fed the same basal diet but given different concentrations of boron-supplemented water. The highest final BW (33.4 ± 0.30 kg), ADFI (376 ± 1.83 g), and ADG (224 ± 1.01 g) appeared in the group receiving 160 mg/L boron (group 4). 160 mg/L boron also decreased drip loss (2.20 ± 0.59), cooking loss (35.3 ± 1.14), and elevated pH value (6.13 ± 0.28) of meat (P < 0.05). Ostrich chicks in the 640 mg/L treatment group (group 6) had the lowest final BW (30.8 ± 1.05 kg) and ADG (208 ± 0.74 g) (P < 0.05). The highest ash (1.35 ± 0.01%) and pH (6.18 ± 0.03) and the lowest protein (20.4 ± 1.74%), drip loss (2.10 ± 0.76%), cooking loss (35.0 ± 0.41%), C18:1 (28.2 ± 0.65%), and C18:3ω3 (2.60 ± 0.51%) appeared in group 6 (P < 0.05) as well. Overall, the optimum concentration of 160 mg/L supplemental boron improved ostrich growth performance and meat quality; however, high concentrations of boron decreased both performance and meat quality.

Effects of supplemental boron on intestinal proliferation and apoptosis in African ostrich chicks / Efectos del boro suplementario sobre la proliferación intestinal y apoptosis en polluelos de avestruz africana

Boron is an essential trace element which plays an important role in process of metabolism and the function of the tissues. However, the effects of boron on the intestinal cells in African ostrich chicks are poorly reported. Therefore, this study was designed to investigate the role of boron on proliferation and apoptosis of the intestinal cells. A total of 36, ten day-old ostrich chicks were randomly divided into six groups and fed on the same basal diet supplemented with 0, 40, 80, 160, 320 and 640 mg/L boric acid in drinking water for 80 days. Proliferatingcell nuclearantigen (PCNA) wasused to test the proliferation indexof intestine in different group byimmunohistochemicalstaining (IHC). Apoptoticcellsofintestinewere detectedbyDutp-biotin nick end labeling (TUNEL) reaction and evaluated by integral optical density (IOD). Results showed that proliferationof intestinal cells significantly increased in groups of 80, 160, 320 and 640 mg/L. TUNEL reaction showed that apoptosis significantly decreased in 80 mg/L groups, while significantly increased in high dose of boron groups (320 and 640 mg/L), especially inepithelium. In conclusion, low dose of boron-supplemented water could promote cell proliferation and depress apoptosis, while high dose of boron could cause intestinal apoptosis and thus we found increased proliferation of intestine cell as a compensatory adaption. These findings may support optimal dosage of boron that could protect the development of ostrich intestine, while high dosage of boron could suppress it, or even has toxic effects on it.

El boro es un elemento esencial que desempeña un importante rol en el proceso del metabolismo y en la función de los tejidos. Sin embargo, existe poca información de los efectos del boro en las células intestinales de polluelos de avestruz Africana. Por lo tanto, este estudio fue diseñado para investigar el papel del boro sobre la proliferación y la apoptosis de las células intestinales. Un total de 36 polluelos de avestruz de diez días se dividieron, aleatoriamente, en seis grupos y se alimentaron con una misma dieta basal suplementada con 0, 40, 80, 160, 320 y 640 mg/L de ácido bórico en agua potable durante 80 días. Se utilizó el antígeno nuclear celular de células en proliferación (PCNA) para probar el índice de proliferación de intestino en diferentes grupos por tinción inmunohistoquímica. Las células apoptóticas del intestino fueron detectadas por dUTP-biotina nick etiquetado para reacción (TUNEL) y evaluadas por la densidad óptica integrada (DOI). Los resultados mostraron que la proliferación de las células intestinales aumentó significativamente en los grupos de 80, 160, 320 y 640 mg /L. La reacción TUNEL mostró que la apoptosis se redujo significativamente en los grupos de 80 mg/L, mientras que el aumento fue significativo en grupos tratados con dosis alta de boro (320 y 640 mg/L), especialmente en el epitelio. En conclusión, la baja dosis de boro en agua suplementada podría promover la proliferación celular y deprimir la apoptosis, mientras que altas dosis de boro podrían provocar apoptosis intestinal y, por lo tanto, se halló una mayor proliferación de las células del intestino como una adaptación compensatoria. Estos hallazgos indican que una dosis óptima de boro podría proteger el desarrollo del intestino del avestruz, mientras que altas dosis de boro podrían suprimirla, o incluso tener efectos tóxicos sobre ella.