Immune-endocrine interactions in agricultural species: chromium and its effect on health and performance

Events with Different Emotional Valence Affect the Eye's Lacrimal Caruncle Temperature Changes in Sheep

Infrared thermography (IRT) has been recently applied to measure lacrimal caruncle temperature non-invasively since this region is related to the sympathetic response, and it seems a promising technique that is able to infer negative emotions in sheep (e.g., fear). However, the scientific literature so far is limited in understanding whether a caruncle's temperature changes also in response to positive emotional states in sheep. Through classical conditioning, we aimed to assess how a positive or a negative event affects the physiological (lacrimal caruncle temperature measured with IRT and cortisol levels) and behavioral responses of sheep (ear position). Fourteen ewes from the same flock were randomly assigned to two treatment groups: positive (n = 7) and negative (n = 7). Each group was then trained through classical conditioning to associate a neutral auditory (ring bell) stimulus to an oncoming event: for the positive group, the presence of a food reward (maize grains), while for the negative one, the opening of an umbrella. After three weeks of training, before (at rest) and after (post-treatment), lacrimal caruncle temperature was non-invasively measured via IRT, and saliva samples were gently collected to measure cortisol levels. During treatment, sheep behavior was videorecorded and then analyzed using a focal animal sampling technique. At rest, the eye's lacrimal caruncle temperature was similar in both groups, while post-treatment, a significant increase was shown only in the negative group (t-test; p = 0.017). In the anticipation phase, sheep in the positive group kept their ears forward longer compared to those in the negative one (Mann-Whitney; p < 0.014), 8.3 ± 2.1 s and 5.2 ± 4.2 s, respectively. The behavioral response observed reflects a learnt association between a neutral stimulus and events with different emotional valence. Cortisol concentration slightly increased in both groups post-treatment. Our results confirm that IRT is a non-invasive technique that can be useful when applied to assess how positive and negative events may affect the physiological response in sheep.

Effects of dietary supplementation of chromium methionine chelate on growth performance, oxidative stress, hematological indices, and carcass traits of broiler chickens

This study was conducted to evaluate the dietary effects of chromium methionine (Cr-Meth) chelate on growth performance, oxidative stress parameters, blood biochemistry, and carcass traits of broiler chickens. An experiment was conducted on 34,000 1-day-old straight-run broiler chicks (Indian River; 42.0 ± 0.03) at a commercial farm. The chicks were divided randomly into 3 groups; the first group contained 17,000 birds, which used as a control, whereas the second and third groups consisted of 7000 and 10,000 birds, respectively, with 5 replicates per group. A completely randomized design was used. The birds were fed the experimental diets containing graded levels of Cr-Meth chelate: 0 (control), 50, and 100 g/ton. This compound consisted of chromium (0.4%) chelated with methionine, and it supply the diets with 200 and 400 ppb Cr for the used levels of 50 and 100 g/ton feed, respectively. Growth performance indices (body weight, body weight gain, feed intake, and feed conversion ratio) were measured throughout the experiment. At the end of experiment, 10 birds per treatment were slaughtered, and the carcass yield with relative weight of the internal organs was determined. Also, blood samples were taken and analyzed for glutathione peroxidase activity, malondialdehyde, ALT, AST, total protein, albumin, glucose, urea, creatinine, triglycerides, and total cholesterol. It was found that Cr-Meth improved the body weight, weight gain, feed intake, and feed conversion ratio of broilers. Moreover, it reduced the mortality rate of birds. The chelated chromium can alleviate the oxidative status of birds by increasing the plasma glutathione peroxidase activity and reducing the serum malondialdehyde level. It was observed that the effects of 100 g/ton Cr-Meth chelate on performance indices, mortality rate, and oxidative stress parameters were better than that of 50 g/ton inclusion rate. Supplementation of Cr-Meth increased the total protein level, but reduced the glucose, total cholesterol, and triglyceride concentrations in the blood serum. In addition, it increased the carcass yield and reduced the abdominal fat percentage of the birds’ carcass. Therefore, chromium can be included in diets of broilers at a rate of 200 to 400 ppb, and the higher concentration was more effective than the lower one. So, it can be recommended to use Cr-Meth chelate in broiler diets at 100 g/ton to improve the productive performance and reduce the oxidative stress of birds.

Impact of Chromate and Dichromate on Lysozyme Stability: A Spectroscopic and Molecular Docking Investigation

A comparative study of interaction between Lysozyme (Lyz) with two hexavalent chromate ions; chromate and dichromate; which are prevalently known for their toxicity, was investigated using different spectroscopic techniques along with molecular docking study. Both steady-state and time-resolved studies revealed that the addition of chromate/dichromate is responsible for strong quenching of intrinsic fluorescence in Lyz and the quenching is caused by both static and dynamic quenching mechanism. Different binding and thermodynamic parameters were also calculated at different temperatures from the intrinsic fluorescence of Lyz. The conformational change in Lyz and thermodynamic parameters obtained during the course of interaction with chromate/dichromate were well-supported by the molecular docking results.

The role of dietary chromium supplementation in relieving heat stress of juvenile blunt snout bream Megalobrama amblycephala

The present study assessed the role of dietary chromium (Cr) supplementation in relieving heat stress (HS) of juvenile blunt snout bream Megalobrama amblycephala. The supplemented Cr contents by chromium picolinate (Cr-Pic) was 0 mg/kg (control group), 0.4 mg/kg, 1.6 mg/kg and 12.0 mg/kg, respectively. The fish continued to be fed four diets at suitable temperatures (26 °C) for 2 weeks, and then the temperature was then heated up to 33 °C through thermo-regulated system. The results showed that Cr supplementation had no significant effect on the immune indices and antioxidant indices before HS (P > 0.05). However, Cr supplementation played an important role in relieving HS. After HS, compared with the control group, 1.6 mg/kg and 12.0 mg/kg Cr supplementation groups significantly lowered the plasma glucose level and aspartate transaminase (AST) activity (P < 0.05), and 0.4 mg/kg and 1.6 mg/kg Cr supplementation groups significantly lowered alanine aminotransferase (ALT) activity (P < 0.05). 0.4 mg/kg and 1.6 mg/kg supplementation groups significantly improved hepatic total superoxide dismutase (T-SOD) activity (P < 0.05). Furthermore, 0.4mg/kg-12.0 mg/kg Cr supplementation groups significantly improved the activities of hepatic glutathione peroxidase (GPx) and catalase (CAT) and lowered hepatic malondialdehyde (MDA) level in liver (P < 0.05). The mRNA levels of hepatic copper zinc superoxide dismutase (Cu/Zn-SOD), CAT and GPx were significantly improved in 0.4mg/kg-12.0 mg/kg supplementation Cr groups (P < 0.05), however, there was no significant variation of hepatic manganese superoxide dismutase (Mn-SOD) mRNA levels under different levels of supplementation (P > 0.05). Significantly lower mRNA levels of hepatic pro-inflammatory cytokines observed in 0.4mg/kg-12.0 mg/kg Cr supplementation groups including tumour necrosis factor-α (TNF-α), interleukin 1β (IL-1β) and interleukin 8 (IL-8) (P < 0.05), and 0.4mg/kg-12.0 mg/kg Cr supplementation significantly improved the relative expressions of hepatic heat shock protein 70 (HSP70) and heat shock protein 90 (HSP90) (P < 0.05). The present study indicated that dietary Cr supplementation might have no significant effect on immune capacity and antioxidant capacity under normal physiological conditions, whereas it played an important role in relieving HS.

Effect of Chromium Nanoparticles on Physiological Stress Induced by Exogenous Dexamethasone in Japanese Quails

Chromium (Cr), as an essential trace element, plays a critical role in carbohydrate, protein, and lipid metabolism in animals. It has been suggested that the beneficial effects of Cr increase by environmental stresses, which lead to greater Cr effects on stressed animals. The objective of the present study was to evaluate the response of physiologically stressed Japanese quails (Coturnix japonica) to dietary chromium nanoparticle (Nano-Cr) supplementation. The stress was induced by adding dexamethasone (0.6 mg/kg BW) to Japanese quails' diet from 17 to 22 days of age. A total of 360 birds were randomly allocated to six dietary treatments with four replicates each having 15 birds: negative control diet (no-stress, no-additive; NC), positive control diet (stress, no-additive; PC), and stress additive diets including four diets containing 200, 400, 800, and 1200 μg/kg of Nano-Cr. Performance and haematological parameters were affected (P < 0.05) by physiological stress though they were not affected by adding Nano-Cr. Comparison of diets containing Nano-Cr levels and stress no-additive diets, at 23 days of age, was indicative of a positive linear relationship (P < 0.05) between dietary Nano-Cr levels and feed intake and average daily gain. Furthermore, white blood cell (WBC) count as well as haematocrit level increased (P < 0.05) as the level of supplied Nano-Cr increased. A negative relationship (P < 0.05) was observed between Nano-Cr levels and heterophil percentage and heterophil/lymphocyte ratio. On day 35, increased dietary Nano-Cr improved (P < 0.05) weight gain, live body weight, energy/protein utilization efficiency, and WBC count. In conclusion, supplementation of diet with optimum concentration of Nano-Cr revealed alleviation of negative effects of physiological stress in quails.

Nutritional strategies to alleviate heat stress in pigs

Pigs are comparatively less heat tolerant than other species of production animals, which poses challenges for stock productivity and management during seasonal heat waves that occur in summer. The issues surrounding heat and pig production are predicted to increase, based on the actions of climate change increasing the intensity, frequency and duration of heat waves. Furthermore, future growth areas of pig production are going to be in tropical regions such as South-east Asia and Latin America. Efforts by the pig to dissipate excess body heat come at a cost to health and divert energy away from growth, compromising efficient pig production. Management of heat stress requires multiple strategies, and recent research is improving the understanding of the application of nutritional strategies to ameliorate the effects of heat stress. In particular the use of feed additives is an important, flexible and economical method to alleviate heat stress and the intensive nature of pig production lends itself to the use of additives. Some specific examples include antioxidants, betaine and chromium, which have been proved effective or being tested in mitigating some certain impacts of heat stress in pigs. The aim of this review is to summarise recent advances in the nutritional management of heat stress in pigs.

Body condition, energy balance and immune status of periparturient Murrah buffaloes (Bubalus bubalis) supplemented with inorganic chromium

Periparturient Murrah buffaloes were used to determine whether body condition, energy balance and immune status are affected by inorganic Cr supplementation. Twenty-four Murrah buffaloes were blocked into four groups having six animals in each group and fed for 60 days pre-partum to 150 days post-partum. Feeding regimen was same in all the groups except that these were supplemented with 0.0, 0.5, 1.0 and 1.5 of Cr per kilogram of dry matter (DM) in the four respective groups. Buffaloes were weighed at fortnightly intervals. Blood samples were collected from the jugular vein at days -60, -30, -15, -7, 0, 7, 15, 30, 60, 90, 120 and 150 of experimental feeding for the estimation of non-esterified fatty acid (NEFA), beta-hydroxybutyric acid (BHBA), Cr level, lymphocyte proliferation, neutrophil phagocytic activity, plasma total immunoglobulin (TIg), immunoglobulin G (IgG) and cortisol levels. Results revealed that with approaching parturition, dry matter intake (DMI), immune response and plasma Cr level decreased (P < 0.05) gradually and minimum values were observed on the day of parturition in all groups. In contrast, body condition score (BCS), plasma NEFA and BHBA concentrations showed increasing (P < 0.05) trends towards calving and level decreased after calving. Dietary Cr supplementation did not have any effect on DMI and BCS, but immune response and plasma Cr concentration showed a positive correlation with dietary Cr supplementation. Buffaloes supplemented with 1.5 mg/kg Cr had significantly (P < 0.05) low plasma NEFA and BHBA concentrations. The results of present findings indicated that dietary inorganic Cr supplementation reduced lipid mobilization and improved immune response in periparturient buffaloes.

Influence of chromium propionate on the carcass characteristics and immune response of commercial broiler birds under normal rearing conditions

The study investigated the effect of supplementation of chromium propionate at different dosage levels (100 to 3,200 µg/kg of elemental chromium in feed) on the performance, carcass characteristics, and immune response of broiler birds. The study was conducted on male broiler chickens (Cobb 400) for a period of 42 d as per the completely randomized design. Seven hundred 1-d-old birds were randomly segregated into 7 treatment groups, each with 10 replicates, and each replicate having 10 birds. Weight gain, feed intake, carcass characteristics, immune response, and the serum biochemical parameters of birds were studied during the supplementation period. There was no significant response to chromium supplementation on weight gain, feed intake, FCR, and lymphoid organ weights for the overall study period of 42 d. With increased chromium dosage, the breast meat yield improved linearly (P = 0.045). Antibody response to Newcastle disease vaccination improved quadratically (P = 0.001) with increased dose of chromium in the diet. Improved cell-mediated immune response was indicated by the increase (quadratic, P = 0.00) in lymphocyte proliferation ratio with increased dose of chromium supplementation. Heterophil:lymphocyte ratio decreased (quadratic, P = 0.004) with chromium propionate dosage, suggestive of reduced stress levels. Chromium propionate supplementation also reduced serum glucose levels (quadratic, P = 0.008) and improved (quadratic, P = 0.016) the total protein levels.

Analysis of immune-relevant genes expressed in spleen of Capra hircus kids fed with trivalent chromium

Chromium is a biologically important element for humans and laboratory animals. Although the favorable effects of trivalent chromiumon immune responses of studied animals have been well documented, the precise mechanisms by which the chromium acts on immune system is relatively poor studied. In this study, real-time qPCR technique was employed to evaluate the expression profiles of four immune-related genes (B2M, MHCA, MHCB, and Rap2A) in spleens of the domestic goats, Capra hircus, feeding on four different levels of supplemental chromium (0, 0.5, 1, and 1.5 mg/day) as chromium– methionine. The results showed that 1.5 mg/day of supplemental chromium significantly increased the expression of the four studied genes (P <0.01). Since the studied genes play important roles in development, activation, and migration of lymphocytes, their increased expression seems to be an unknown mechanism by which chromium impose reinforcing effects on immune system. Therefore, supplemental chromium can be potentially used to improve immune responses especially in animals experiencing any type of stress such as invasion by a pathogen.

Physiological, biochemical and histometric responses of Nile tilapia (Oreochromis niloticus L.) by dietary organic chromium (chromium picolinate) supplementation

Chromium has been recognized as a new and important micro-nutrient, essential for both human and animal nutrition. This study was conducted to evaluate the appropriateness and/or the use of safety level of dietary chromium picolinate (Cr-Pic), and its effects on the physiological responses, the histometric characteristics, and the chemical analysis of dorsal muscles of mono-sex Nile tilapia, Oreochromis niloticus. A total of 420 fingerlings (28.00 ± 0.96 g) were randomly distributed into 21 fiberglass tanks representing seven treatments at a rate of 20 fish m⁻³. The control fish group (T₁) was fed a Cr-Pic free basal diet. Other fish groups were fed the basal diet supplemented with 200 (T₂), 400 (T₃), 600 (T₄), 800 (T₅), 1000 (T₆) and 1200 μg Cr-Pic kg⁻¹ diet (T₇). Diets were offered to fish at a feeding rate of 3% of life body weight for 12 weeks. Results revealed that blood hematological parameters (hemoglobin, red blood cells, packed cell volume, mean corpuscular hemoglobin concentration, blood platelets, and white blood cells lymphocytes); serum biochemical measurements (total testosterone, high density lipoprotein, total protein, albumin, and globulin); and the dry matter and crude protein of the fish dorsal muscles all have significantly increased (P ⩽ 0.05) in the T₃ treatment compared with the other treatments. Meanwhile, no significant differences were found among all treatments with regard to the histometric characteristics. It can be concluded that Cr-Pic at 400 μg kg⁻¹ diet (T₃) seems to be the most appropriate level for O. niloticus fingerlings.

Effects of different levels of organic and inorganic chromium on growth performance and immunocompetence of broilers under heat stress

This experiment was carried out to investigate the effects of different levels of organic and inorganic chromium on the performance, immune function and some serum mineral concentrations of broilers under heat stress condition (23.9-37°C cycling). A total of 150 one-day-old broiler chicks according to a completely randomized design were assigned into five treatment groups. Each treatment consisted of three replicates and each replicate contained ten chicks. Chicks were fed on corn-soybean meal basal diets with added different concentrations of chromium (0, 600 and 1,200 μg kg(-1) chromium chloride or 600 and 1,200 μg/kg chromium L-methionine) from 1 to 49 days of age. Humoral immunity was assessed by intravenous injection of 7% sheep red blood cell (SRBC) followed by evaluation of serum for antibody titers in primary and secondary responses. Cell-mediated immunity was assessed by the cutaneous basophil hypersensitivity (CBH) test to phytohemagglutinin (PHA)-P at day 32 and PHA-M at day 48. Heterophil/lymphocyte (H/L) ratio was also measured as a reliable indicator of stress. The body mass, feed intake and conversion ratio were not influenced by dietary chromium (P > 0.05). Dietary supplementation of both organic and inorganic chromium significantly increased primary and secondary antibody responses (P < 0.01), and also improved H/L ratio (P < 0.05), CBH response (P < 0.01) as well as relative weights of thymus (P < 0.05) and spleen (P < 0.01). Both dietary organic and inorganic chromium caused an increase in serum concentrations of Cr and Zn (P < 0.01), but decreased the serum concentration of Cu (P < 0.01). These results suggest that supplemental chromium especially in organic form offers a good management practice to reduce heat stress-related depression in immunocompetence of broiler chicks.

Enhancement of the acute phase response to a lipopolysaccharide challenge in steers supplemented with chromium

The study examined the effect of chromium supplementation on the response of steers to an LPS challenge. Steers received a premix that added 0 (control; n = 10) or 0.2 mg/kg of chromium ( n = 10) to the total diet on a dry matter basis for 56 d. Steers were fitted with jugular catheters and rectal temperature (RT) recording devices on d 52. Blood samples were collected and sickness behavior scores assigned to each steer relative to an LPS challenge (0.5 µg/kg) on d 55. Pre-LPS RT were greater in chromium-supplemented than in control steers. Post-LPS RT increased in both treatments, with control steers producing a greater change in RT than chromium-supplemented steers. Sickness behavior scores were greater in control than in chromium-supplemented steers post-LPS ( P = 0.03). Cortisol concentrations did not differ between treatments pre-LPS. Post-LPS cortisol concentrations increased but did not differ due to treatment. Concentrations of IL-4 increased post-LPS but were not affected by treatment pre- or post-LPS. Treatment did not affect pre-LPS TNF-α or IFN-γ. Post-LPS TNF-α and IFN-γ increased in both treatments, with chromium-supplemented steers producing greater TNF-α ( P = 0.005) and IFN-γ ( P = 0.004) than control steers. Pre-LPS IL-6 was greater ( P = 0.027) in chromium-supplemented steers than in control steers. Post-LPS IL-6 increased in both treatments and was greater ( P < 0.001) in chromium-supplemented than in control steers. These data suggest that chromium supplementation enhances the acute phase response of steers to an LPS challenge, which may expedite recovery.

Chromium(III) nanoparticles affect hormone and immune responses in heat-stressed rats

This study was conducted to evaluate the effects of chromium nanoparticles (CrNano) on the hormone and immune responses of rats in heat stress condition. A total of 80 male Sprague-Dawley rats were randomly assigned to four dietary treatment groups (n = 20). The first group was offered a basal diet as a control. The second, third, and fourth groups received basal diet supplemented with 150, 300, and 450 microg/kg Cr, respectively, in the form of CrNano. At the end of the 8-week trial, growth performance, food utilization, and sera concentrations of hormones, immunoglobulins, and alexins were determined. Lymphocyte proliferation activity, antibody response to injected sheep red blood cells (SRBCs), and phagocytosis of peritoneal macrophages were determined by (3)H-thymidine uptake method, plaque-forming cells (PFC) assay, and ingesting chicken red blood cells test, respectively. The results indicated that rats that received CrNano exhibited no changes in growth rate and food efficiency compared to the control group. However, dietary supplementation of 150, 300, and 450 microg/kg Cr from CrNano significantly decreased serum concentrations of insulin and cortisol, increased sera levels of insulin-like growth factor I and immunoglobulin G, and enhanced the lymphoproliferative response, anti-SRBC PFC response, and phagocytic activity of peritoneal macrophages. These results suggest that dietary supplementation of Cr as CrNano affects hormone and immune status in heat-stressed rats.

Influence of Stress and Nutrition on Cattle Immunity

Today, the scientific community readily embraces the fact that stress and nutrition impact every physiologic process in the body. At last, the specific mechanisms by which stress and nutrition affect the immune function are being elucidated. The debate among animal scientists concerning the definition and quantification of stress as it relates to animal productivity and well-being is ongoing. However, an increased appreciation and understanding of the effects of stress on livestock production has emerged throughout the scientific community and with livestock producers. The intent of this article is to provide an overview of the general concepts of stress and immunology, and to review the effects of stress and nutrition on the immune system of cattle.

Chromium Supplementation Enhances Antibody Response to Vaccination with Tetanus Toxoid in Cattle

Nineteen multiparous late-pregnant dairy cows were divided into an experimental group (n = 10) and a control group (n = 9). Animals in the experimental group were fed a diet supplemented with chromium chelate admixed into wheat meal at 5 mg per animal per day. The supplementation was started 4 weeks before calving and stopped by the end of week 3 after calving. All the cows were vaccinated with tetanus toxoid in the fifth and sixth week of lactation. Monitoring of the characteristics of non-specific immunity did not show any significant between-group differences in total and differential leucocyte counts, percentages of lymphocyte subpopulations, activities of lectin-stimulated lymphocytes, phagocytic activities, and the contents of total immunoglobulins and lysozyme in blood sera. Tetanus toxoid-specific antibody titres, those of the IgG2 isotype in particular, were higher in the experimental group than in the control animals. These results indicate that chromium supplementation at the level used in this experiment modulated the regulation of functions of the immune system.