Poultry in commercial settings are exposed to a range of stressors. A growing body of information clearly indicates that excess ROS/RNS production and oxidative stress are major detrimental consequences of the most common commercial stressors in poultry production. During evolution, antioxidant defence systems were developed in poultry to survive in an oxygenated atmosphere. They include a complex network of internally synthesised (e.g., antioxidant enzymes, (glutathione) GSH, (coenzyme Q) CoQ) and externally supplied (vitamin E, carotenoids, etc.) antioxidants. In fact, all antioxidants in the body work cooperatively as a team to maintain optimal redox balance in the cell/body. This balance is a key element in providing the necessary conditions for cell signalling, a vital process for regulation of the expression of various genes, stress adaptation and homeostasis maintenance in the body. Since ROS/RNS are considered to be important signalling molecules, their concentration is strictly regulated by the antioxidant defence network in conjunction with various transcription factors and vitagenes. In fact, activation of vitagenes via such transcription factors as Nrf2 leads to an additional synthesis of an array of protective molecules which can deal with increased ROS/RNS production. Therefore, it is a challenging task to develop a system of optimal antioxidant supplementation to help growing/productive birds maintain effective antioxidant defences and redox balance in the body. On the one hand, antioxidants, such as vitamin E, or minerals (e.g., Se, Mn, Cu and Zn) are a compulsory part of the commercial pre-mixes for poultry, and, in most cases, are adequate to meet the physiological requirements in these elements. On the other hand, due to the aforementioned commercially relevant stressors, there is a need for additional support for the antioxidant system in poultry. This new direction in improving antioxidant defences for poultry in stress conditions is related to an opportunity to activate a range of vitagenes (via Nrf2-related mechanisms: superoxide dismutase, SOD; heme oxygenase-1, HO-1; GSH and thioredoxin, or other mechanisms: Heat shock protein (HSP)/heat shock factor (HSP), sirtuins, etc.) to maximise internal AO protection and redox balance maintenance. Therefore, the development of vitagene-regulating nutritional supplements is on the agenda of many commercial companies worldwide.

Antioxidant Defence Systems and Oxidative Stress in Poultry Biology: An Update

Boron is an essential plant micronutrient taken up via the roots mostly in the form of boric acid. Its important role in plant metabolism involves the stabilization of molecules with cis-diol groups. The element is involved in the cell wall and membrane structure and functioning; therefore, it participates in numerous ion, metabolite, and hormone transport reactions. Boron has an extremely narrow range between deficiency and toxicity, and inadequate boron supply exhibits a detrimental effect on the yield of agricultural plants. The deficiency problem can be solved by fertilization, whereas soil boron toxicity can be ameliorated using various procedures; however, these approaches are costly and time-consuming, and they often show temporary effects. Plant species, as well as the genotypes within the species, dramatically differ in terms of boron requirements; thus, the available soil boron which is deficient for one crop may exhibit toxic effects on another. The widely documented intraspecies genetic variability regarding boron utilization efficiency and toxicity tolerance, together with the knowledge of the physiology and genetics of boron, should result in the development of efficient and tolerant varieties that may represent a long-term sustainable solution for the problem of inadequate or excess boron supply.

Boron Toxicity and Deficiency in Agricultural Plants.

Minerals and trace elements are micronutrients that are essential to the human body but present only in traceable amounts Nonetheless, they exhibit well-defined biochemical functions Deficiencies in these micronutrients are related to widespread human health problems This review article is focused on some of these minerals and trace element deficiencies and their consequences in diabetes and insulin resistance The levels of trace elements vary considerably among different populations, contingent on the composition of the diet In several Asian countries, large proportions of the population are affected by a number of micronutrient deficiencies Local differences in selenium, zinc, copper, iron, chromium and iodine in the diet occur in both developed and developing countries, largely due to malnutrition and dependence on indigenous nutrition These overall deficiencies and, in a few cases, excess of essential trace elements may lead to imbalances in glucose homeostasis and insulin resistance The most extensive problems affecting one billion people or more worldwide are associated with inadequate supply of a number of minerals and trace elements including iodine, selenium, zinc, calcium, chromium, cobalt, iron, boron and magnesium This review comprises various randomized controlled trials, cohort and case-controlled studies, and observational and laboratory-based studies with substantial outcomes of micronutrient deficiencies on diabetes and insulin resistance in diverse racial inhabitants from parts of Asia, Africa, and North America Changes in these micronutrient levels in the serum and urine of subjects may indicate the trajectory toward metabolic changes, oxidative stress and provide disease-relevant information

Role of Minerals and Trace Elements in Diabetes and Insulin Resistance.

Hesperetin relieves cisplatin-induced acute kidney injury by mitigating oxidative stress, inflammation and apoptosis.

The hormetic dose-response mechanism: Nrf2 activation

Boron is an essential mineral that plays an important role in several biological processes. Boron is required for growth of plants, animals, and humans. There are increasing evidences of this nutrient showing a variety of pleiotropic effects, ranging from anti-inflammatory and antioxidant effects to the modulation of different body systems. In the past few years, the trials showed disease-related polymorphisms of boron in different species, which has drawn attention of scientists to the significance of boron to health. Low boron profile has been related with poor immune function, increased risk of mortality, osteoporosis, and cognitive deterioration. High boron status revealed injury to cell and toxicity in different animals and humans. Some studies have shown some benefits of higher boron status, but findings have been generally mixed, which perhaps accentuates the fact that dietary intake will benefit only if supplemental amount is appropriate. The health benefits of boron are numerous in animals and humans; for instance, it affects the growth at safe intake. Central nervous system shows improvement and immune organs exhibit enhanced immunity with boron supplementation. Hepatic metabolism also shows positive changes in response to dietary boron intake. Furthermore, animals and human fed diets supplemented with boron reveal improved bone density and other benefits including embryonic development, wound healing, and cancer therapy. It has also been reported that boron affects the metabolism of several enzymes and minerals. In the background of these health benefits, low or high boron status is giving cause for concern. Additionally, researches are needed to further elucidate the mechanisms of boron effects, and determine the requirements in different species.

The Physiological Role of Boron on Health.

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.

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

Received: Revised: Accepted: February 08, 2015 April 21, 2015 May 08, 2015 Toll-like receptor 4 (TLR4) plays a significant role in modulation of immunological tolerance in reproductive tract of human female. To better understand the functions of TLR4 in establishing and maintaining the pregnancy in pigs, this study was performed to investigate the cellular expression and distribution patterns of TLR4 in the uterus of pregnant Yorkshire pigs. For this purpose, the uterine tissues from pregnant gilts were obtained on days 15, 26, 50 and 95 of gestation. The distribution of TLR4 in the uterus was analyzed by immunohistochemical technique, using an antibody against TLR4. TLR4 was found in uterine luminal epithelium, uterine glands, trophoblasts and placental blood vessels; TLR4 expression in the trophoblast cells and uterine luminal epithelium, on days 15 and 26 of gestation was higher than that on days 50 and 95 of gestation, and there was nearly same expression between days 50 and 95 of gestation. In uterine glands, the expression of TLR4 protein was nearly equal at all stages of gestation. These results indicated that TLR4 is expressed in different histological layers of the uterus during the pregnancy and it changes with the advancement in gestational stages. These results provided novel information about cellular distribution and the functions of TLR4 in modulating immune tolerance in pig uterus during pregnancy. ©2015 PVJ. All rights reserved

Expression Patterns of Toll-Like Receptor 4 in Pig Uterus during Pregnancy

Received: Revised: Accepted: December 24, 2012 August 22, 2013 October 18, 2013 The expression of visfatin in ovary and the changes of IFN-γ in peripheral blood were detected by the immunohistochemical method and the double antibody sandwich ELISA test method to investigate the distribution situation of visfatin in the ovary and its regulatory effect on the development of mouse ovarian follicles. Our research showed that visfatin positive cells were mainly located in the follicle cell layer of ovary in different developmental stages. The strongly positive staining were seen in the cells of the granular layer of growing follicle, the positive cells were numerous and compressed, and the cells of the granular layer of mature follicle also showed significantly positive reaction though their amount was fewer. Visfatin positive cells were rarely expressed and were weakly positive in oocytes, and it lacked in germinal epithelium, theca folliculi, follicular matrix and atretic follicle. Statistical results showed that the visfatin level of the control group was not significantly different from that of the protein group or the antibody group in the peripheral blood, while the protein group was significantly different from antibody group (P<0.05). The above results suggested that visfatin positive cells are widely expressed in the grained layer of ovarian follicle in different development stages, which shows its links with the development of follicular. The effect of visfatin on the level of IFN-γ in periphery blood tips the role of visfatin in regulating the development of follicles. ©2013 PVJ. All rights reserved

The expression of visfatin in mouse ovary and its regulatory effect on IFN-γ.

Received: Revised: Accepted: February 02, 2015 April 03, 2015 June 15, 2015 This study was to determine the effect of boron supplementation on the morphology of kidney tissue in ostrich chicks. A total of 48 newly hatched ostrich chicks were used and randomly assigned to six groups and exposed to various doses of boric (0, 40, 80, 160, 320, 640 mg/L) in drinking water for 90 days, respectively. The kidneys were removed and tissue sections were stained with HE for morphological examination and semi-quantitative evaluation. Microscopic observation showed that compared with the control group (0 mg/L), the structure of renal corpuscle and renal tubular was clearer in ostrich chicks fed with 40 and 80 mg/L boron. Furthermore, the brush borders were more abundant. On the other hand, in groups fed with 320 and 640 mg/L boron, histopathological degeneration occurred with the characters of cellular swelling and dissociation, loose cytoplasm, nuclear pyknosis, and basement membrane detachment in some tubular cells. Debris deposit was accumulated in the tubular lumen, especially in the proximal tubule. And the percentage of injured tubules was more than 50% in these groups. Moreover, the extent of kidney injury in group receiving 640 mg/L boron was more obvious with increasing tubular dilatation, tubular cell granular degeneration, interstitial inflammation and associated capsular retraction. Taken together, these findings showed that 40 and 80 mg/L boron supplementation may promote the kidney development; while 320 and 640 mg/L boron supplementation have obviously adverse effect, and the toxic effect was dose-dependent. ©2015 PVJ. All rights reserved

Peng KeMei

Papers

The Physiological Role of Boron on Health.

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

Expression Patterns of Toll-Like Receptor 4 in Pig Uterus during Pregnancy

The expression of visfatin in mouse ovary and its regulatory effect on IFN-γ.

Effect of boron administration on the morphology of ostrich chick kidney tissue.