Dietary supplementation of β‐hydroxy‐β‐methylbutyrate in animals – a review

The leucine metabolite β‐hydroxy‐β‐methylbutyrate (HMB) has been studied by many researchers over the last two decades. In particular, the utility of HMB supplementation in animals has been shown in numerous studies, which have demonstrated enhanced body weight gain and carcass yield in slaughter animals; positive immunostimulatory effect; decreased mortality; attenuation of sarcopenia in elderly animals; and potential use in pathological conditions such as glucocorticoid‐induced muscle loss. The aim of this study was to summarize the body of research on HMB supplementation in animals and to examine possible mechanisms of HMB action. Furthermore, while the safety of HMB supplementation in animals is well documented, studies demonstrating efficacy are less clear. The possible reasons for differences in these findings will also be examined.     

Associative effects of supplementing rice straw‐based diet with cornstarch on intake,digestion, rumen microbes and growth performance of Huzhou lambs

Thirty‐six male Hu lambs consuming a rice straw‐based diet were used in a 60‐day trial to study the associative effects of cornstarch supplementation on intake, digestion, ruminal microbial population and growth performance. All animals were fed rice straw ad libitum together with 160 g/day of rapeseed meal and supplemented with cornstarch at levels of 0 (control), 60, 120 or 180 g/day, respectively. Increment of supplementary cornstarch showed little influence on rice straw intake. Optimal growth performance and highest apparent digestibility of organic matter was achieved in the 120 g/day cornstarch group (P < 0.05), while the digestibilities of neutral detergent fiber and crude protein were significantly decreased by 180 g/day cornstarch (P < 0.05). Similar results were observed for carboxymethyl cellulose activity and relative populations of cellulolytic bacteria (Ruminococcus albus, Ruminococcus flavefaciens and Fibrobacter succinogene). Blood urea nitrogen was reduced by supplementary cornstarch, indicating enhanced protein utilization efficiency. Carcass traits were all significantly improved by supplementary cornstarch. These results suggested that proper amounts of starch supplementation (within 0.5% BW) has little adverse effect on forage utilization, but could effectively improve growth performance. High levels of cornstarch, however, would decrease cellulase activity and populations of cellulolytic bacteria, and hence the digestibility of forage.     

The effect of dietary long‐chain omega‐3 fatty acid supplementation on owner’s perception of behaviour and locomotion in cats with naturally occurring osteoarthritis

The aim of this randomized, double‐blinded, placebo–controlled, cross‐over designed study was to demonstrate the clinical effect, registered by a survey, of a 10‐week period of omega‐3 fatty acid supplementation of the diet (1.53 g eicosapentaenoic acid (EPA) and 0.31 g DHA, both per 1000 kcal ME, equivalent to the complete diet) of 16 cats with radiologically documented, naturally occurring osteoarthritis (OA), in comparison with a 10‐week period of supplementation with corn oil (0.00 g EPA and 0.00 g DHA, both per 1000 kcal ME). Cats on the fish oil revealed higher activity level (p = 0.07), more walking up and down the stairs (p = 0.07), less stiffness during gait (p = 0.03), more interaction with the owner (p = 0.07) and higher jumps (p = 0.03) compared to those on corn oil supplementation. In conclusion, supplementation of long‐chain omega‐3 polyunsaturated fatty acids changes the owner’s perception of some aspects of behaviour and locomotion in cats with naturally occurring OA.     

Localized cowpox infection in a 5‐month‐old Rottweiler

Cowpox virus (CPXV) infections are a sporadic cause of localized or disseminated skin disease in domestic animals and humans in Europe. Rodents are considered the primary reservoir host for CPXV. Cats can become infected by close contact with rodents and are the most important source of human infections. Recently, public awareness has also been drawn to CPXV infections by an outbreak of rat to human infections in central Europe. In dogs, CPXV infections are rare. Here we report a case of a 5‐month‐old Rottweiler with a focal nodule on the muzzle. The lesion was fully excised, and recovery was uneventful. The preliminary diagnosis of a CPXV infection was established by the characteristic inclusion bodies on histopathological examination. The diagnosis was confirmed by electron microscopy and polymerase chain reaction (PCR). Sequencing of the PCR product led to a 231 bp sequence of the orthopoxvirus HA gene that was identical to a CPXV strain previously isolated from a cat. This is the third documented case of a canine CPXV infection.     

The stadium effect: rodent damage patterns in rice fields explored using giving‐up densities

Rodents are globally important pre‐harvest pests of rice. In Southeast Asia, rodent damage to growing rice crops is commonly concentrated towards the center of rice fields, away from the field edge, resulting in a clear pattern known as the “stadium effect.” To further understand this behavior of rodent pests and to develop recommendations for future research and management, we examined the relation between giving‐up densities (GUDs) and damage patterns. In Tanay, Luzon, Philippines, GUD trays containing pieces of coconut in a matrix of sand were placed at 4 different distances from the field edge to quantify the perceived risk of predation in a rice field pest, Rattus tanezumi. GUDs were recorded during a dry and wet season crop at the reproductive and ripening stages of rice. In addition, assessments of active burrows, tracking tile activity and rodent damage to the rice crop, were conducted in the dry season. GUDs were significantly lower in the center of the rice fields than on the field edges, suggesting that rodent damage to rice is greater in the middle of rice fields due to a lower perceived predation risk. Furthermore, this perception of predation risk (or fear) increases towards the field edge and was greatest on the rice bund, where there was no vegetation cover. We discuss the implications for rodent management and rodent damage assessments in rice fields. This is the first documented use of GUDs in a rice agro‐ecosystem in Asia; thus we identify the challenges and lessons learned through this process.     

Fungal phytases: characteristics and amelioration of nutritional quality and growth of non‐ruminants

Fungal phytases are histidine acid phosphatases, a subclass of acid phosphatases, which catalyse the hydrolysis of phytic acid resulting in the release of phosphate moieties and thus mitigate its antinutritional properties. The supplementation of feed with phytases increases the bioavailability of phosphorus and minerals in non‐ruminant animals and reduces the phosphorus pollution due to phosphorus excretion in the areas of intensive livestock production. Although phytases are reported in plants, animals and micro‐organisms, fungal sources are used extensively for the production of phytases on a commercial scale. Phytases have been produced by fungi in both solid‐state fermentation (SSF) and submerged fermentation (SmF). The fungal phytases are high molecular weight proteins ranging from 35 to 500 kDa. They are optimally active within pH and temperature ranges between 4.5 and 6.0, and 45 and 70 °C respectively. Phytate degradation leads to amelioration in the nutritional status of foods and feeds by improving the availability of minerals, phosphorus and proteins in non‐ruminant animals and human beings and thus mitigates the environmental phosphorus pollution. Our article focuses on the role of fungal phytases in improving nutritional value of foods and feeds with concomitant increase in growth of non‐ruminant animals and mitigating environmental phosphorus pollution.     

Comparative study on the regulation of body fluids and mammary circulation at different stages of lactation in crossbred Holstein cattle feeding on different types of roughage

The present study was carried out to evaluate the effect of prolonged feeding of urea‐treated rice straw, compared with feeding of hay, on the regulation of body fluids, milk yield and mammary circulation at early lactation (30 days postpartum), mid‐lactation (120 days postpartum) and late lactation (210 days postpartum) in crossbred Holstein Friesians. Sixteen first lactating crossbred Holstein Friesians (HF), consisting of eight animals of two breed types, 87.5%HF and 50%HF, were selected and each breed was randomly allocated into two groups. Each group, consisting of four animals from the same breed, was fed either 5% urea‐treated rice straw or pangola hay (Digitaria decumbens) as the source of roughage in combination with a similar concentrate throughout the experiments. During the course of lactation there were no significant differences in body weight, heart rate, mean arterial blood pressure, plasma osmolality, plasma volume and blood volume among groups of 87.5%HF animals and 50%HF animals fed either hay or urea‐treated rice straw. Water turnover rate, total body water space and total body water as a percentage of body weight of 50%HF animals were significantly higher than those of 87.5%HF animals fed either hay or urea‐treated rice straw. The packed cell volume was significantly higher in all lactating periods of both groups of 50%HF animals in comparison with 87.5%HF animals. The ratio of DM intake to milk production for 87.5%HF animals fed either hay or urea‐treated rice straw was significantly lower than that of 50%HF animals in early lactation. The udder blood flow and milk secretion of 87.5%HF were significantly higher in early lactation and markedly declined when lactation advanced in comparison with those of 50%HF animals fed either hay or urea‐treated rice straw. The ratio of mammary blood flow to milk yield for all groups was in a similar range during early lactation although it significantly increased in mid‐ and late lactation for both groups of 87.5%HF animals. From these results it can be concluded that both 50%HF and 87.5%HF animals feeding on urea‐treated rice straw as a roughage source do not show any undernutritional effects in comparison with those fed with hay during the course of lactation. The physiological response differences between breeds are that 87.5%HF animals, which have a genetic makeup closer to the exotic bos taurus breed and a high milk yield, show a poor adjustment to the tropical environment and poorer lactation persistency in comparison with 50%HF animals.     

Effects of different dietary protein levels and DL‐methionine supplementation on hair growth and pelt quality in mink (Neovision vision)

The effect of different dietary protein levels and DL‐methionine (Met) supplementation on hair growth and the resulting pelt quality in mink was studied. Four groups of male mink were fed with four isocaloric diets containing 32% (P32), 24% (P24), 16% (P16) or P24+Met (0.8%) crude protein of dry matter (DM) from September to December. Skin biopsies were taken at the pelting. Histological techniques and computer‐assisted light microscopy were used to determine the ratio of activity (ROA) of under hairs and guard hairs respectively. The results showed that when the dietary protein level reduced from 32% to 16%, body length, number and diameter of under hairs and guard hairs of minks declined, and pelt length and pelt weight of minks decreased significantly (p < 0.05). These parameters were similar between P32 and P24 with Met supplementation (p > 0.05). The hair follicle density of the winter coat was not influenced by the dietary protein levels and Met supplementation (p > 0.05). Low‐protein diets content led to a reduction of hair follicle developing to next phase. It was documented that 24% crude protein of DM with Met supplementation during growing‐furring period was sufficient for minks to express their genetic capacity to develop hair follicles and achieve the prime fur characteristics. Overall this study demonstrated that hair growth and hair properties in pelts are very dependent on the dietary protein and Met supply in the growing‐furring period of minks.     

Effects of β-Hydroxy-β-Methylbutyrate and γ-Oryzanol on Blood Biochemical Markers in Exercising Thoroughbred Race Horses

In both the horse and the man, nutritional ergogenic aids have been used to improve physical ability in conjunction with an appropriate training regimen. Although training increases physical condition, the ease of taking a nutritional additive to improve training results explains the demand for supplementation, which may increase mechanical energy of work, delay onset of fatigue, or improve neuromuscular coordination. The purpose of this study was to determine the effects of oral supplementation of β-hydroxy-β-methylbutyrate (HMB) and γ-oryzanol (GO) on indices of exercise-induced muscle damage in Thoroughbred race horses. In this 32-week study, the horses were assigned to either a placebo, GO (3.0 g/d), HMB (15 g/d), or GO and HMB treatment groups. The supplements were administered for the first 16 weeks of the study during the training period before the racing season began. Blood samples were taken at baseline, and then during training, before exercise, immediately after exercise, and 30 minutes after exercise. Heart rate and speed were monitored in each exercise session. Hematocrit, glucose, lactate (LA), creatine phosphokinase, and aspartate aminotransferase were measured before and after each exercise session. Analysis of variance showed a significantly greater increase in postexercise creatine kinase activity in placebo-supplemented group than in the other treatment groups, both in the training period and during the racing seasons (P < .05). Blood LA was higher immediately after exercise in the placebo group compared with the supplemented groups. In conclusion, supplementation with HMB and GO resulted in decreased creatine kinase and LA after exercise. These findings support the hypothesis that HMB and GO supplementation helps to prevent exercise-induced muscle damage.     

Seasonal and dietary effects on Vitamin D deficiencies detected in wild boar from mid‐western Spain

Vitamin D (VitD) is involved in important mammalian physiological mechanisms, such as Ca–P metabolism, bone development and immunological response. VitD deficiencies are frequently detected in domestic animals and related to various health problems (e.g., rickets, bone deformation). However, knowledge about the status of VitD in wildlife species, such as the wild boar, is scarce. The aims of this work were to explore VitD status in wild boar populations from mid‐western Spain and to elucidate the influence of daylight exposure and food supplementation in levels of VitD. Serum concentration of VitD (measured as 25‐hydroxivitaminD) was assessed in 276 wild boar from 27 game estates located in mid‐western Spain using a commercial ELISA kit. In 19 out of 27 estates, the staff supplied a specific VitD‐enriched food (2,000 UI/Kg) ad libitum throughout the year, while in the remaining estates (8), no food was supplied. Blood samples were extracted from hunted animals (198) between October and February of hunting seasons 2016/2017 and 2017/2018, and from live wild boar (78) that were captured, sampled and released (March–September of 2017). The percentage of animals with VitD deficiency (<20 ng/ml), VitD insufficiency (20–30 ng/ml) and VitD sufficiency (>30 ng/ml) was estimated, and the relationship of these levels to factors like sex, age and season was assessed using chi‐square tests. Furthermore, associations between daylight exposure and supplemental food with VitD levels were explored using linear models. Of the studied wild boar population, 82.2% showed a VitD deficiency or insufficiency. VitD deficiencies were more frequent in animals sampled in winter and spring. Furthermore, levels of VitD positively correlated with daylight exposure and supplemental food intake. Ad libitum supplementation with VitD‐enriched food was insufficient to prevent VitD deficiencies in wild boar from November to April, probably because food consumption is lower during this period.     

Rumen‐protected methionine supplementation and fibre production in alpacas (Vicugna pacos)

Sulphur‐containing amino acids are a crucial requirement for fibre production and may be supplemented in the diet of fibre‐producing animals to stimulate fibre growth. The alpaca fibre industry is a developing industry in Australia with high variability in fibre production. To date, there is no evidence whether supplementing the diet of alpacas with sulphur amino acids improves fibre production. We hypothesised that supplementation with the rumen‐protected sulphur amino acid, methionine would increase fibre growth in alpacas. Three groups of eight huacaya alpaca wethers were fed daily a maintenance diet supplemented with 0, 2 or 4 g of rumen‐protected methionine for 7 weeks. Fibre samples were taken at the beginning and end of the study with a blood sample taken by jugular venipuncture prior to feeding on the first day of each week. Methionine supplementation had no effect on fibre diameter (p = 0.92), fibre length (p = 0.91) or fibre yield (p = 0.33). The change of season over the study affected plasma glucose (p < 0.001), plasma urea nitrogen (p < 0.001) and fibre diameter (p < 0.001). The indifference between groups may be due to the maintenance diet supplying sufficient levels of methionine, the lack of genetic potential of the experimental animals to respond to additional methionine or that the supplemental methionine was not protected in alpacas and deaminated for glucose production.     

Equine orbital angiomatosis

Angiomatosis refers to a vascular tumour consisting of several vascular, blood‐filled cavities with a lining of well‐differentiated endothelial cells. This condition is seen in very young cattle as a malformative process and has been documented in other animals as well. In horses, this disease has only rarely been described, with no reported lesions being found within the equine orbit. This report details the clinical findings, surgical exploration, histopathology, and long‐term follow‐up of an aged horse with orbital angiomatosis.     

Clinical features and outcome of dermal squamous cell carcinoma in 193 dogs (1987‐2017)

Squamous cell carcinoma (SCC) is a frequently recognized dermal tumour in dogs and has been described as a common pathology induced by solar ultraviolet radiation exposure. Little has been published about this neoplasm with regard to clinical features and outcome in dogs. This retrospective study included 193 dogs from a single institution histopathologically diagnosed with SCC of the dermis. Thirty‐eight percent of all dogs had documented histopathologic actinic change. The overall median survival time was 1004 days, with the population demonstrating actinic change associated with a significantly longer survival time (median 1359 days, range 16‐3530 days) compared to dogs without actinic change (median 680 days, range 16‐3066 days) and this achieved significance on multivariate analysis (hazard ratio 0.42, 95% confidence interval 0.193‐0.930, P = 0.032). These data demonstrate increased survival of dogs with SCC demonstrating actinic change over those with non‐actinic SCCs, and purports long‐term survival for these animals. Dogs received a variety of treatment approaches as a retrospective study, and future prospective studies will be necessary to investigate whether adjunct therapies such as radiation or chemotherapy offer improvement in survival for dermal SCC in the dog.     

Dose–responses of zinc–methionine supplements on growth,blood metabolites and gastrointestinal development in sheep

The effects of zinc–methionine (Zn‐Met) supplementation on growth, blood metabolites and gastrointestinal development were investigated in two experiments with sheep. The objective of Experiment 1 was to determine the effects of Zn‐Met supplementation on hormones and metabolites involved in growth and energy balance regulation, while Experiment 2 aimed to determine the effects of Zn‐Met on feed intake, body weight, gastrointestinal development and liver glycogen concentration in lamb. The animals were assigned to groups with different concentrations of dietary Zn‐Met (0, 0.4, 0.8 and 1.2 g/day) in both experiments. In Experiment 1, feeding different doses of Zn‐Met increased plasma insulin‐like growth factor 1 (IGF‐1) concentration, but it linearly decreased plasma growth hormone (GH). No differences were observed in blood cortisol, insulin and glucose concentrations among the treatments. In Experiment 2, addition of Zn‐Met to the diets did not lead to changes in the body weights of the lambs. Both average daily gain and dry matter intake (DMI) increased linearly with increasing concentrations of dietary Zn‐Met. Lambs receiving Zn‐Met showed higher liver glycogen concentrations than the control. While significant increases were observed in the villus height and crypt depth in the duodenum and jejunum as a result of Zn‐Met supplementation, no change was detected in blood glucose concentrations (p > 0.05). Our findings suggest that dietary Zn‐Met may improve growth, energy balance and gastrointestinal development in sheep.     

Effects of energy supply and nicotinic acid supplementation on serum anti‐oxidative capacity and on expression of oxidative stress‐related genes in blood leucocytes of periparturient primi‐ and pluriparous dairy cows

The periparturient period is accompanied by metabolic and oxidative stress. Niacin is known to decrease lipolysis but is also reported to have anti‐oxidative effects. Therefore, we examined the effects of energy supply and a nicotinic acid (NA) supplementation on anti‐oxidative serum parameters and on the expression of oxidative stress‐related genes in blood leucocytes of periparturient dairy cows, differing in parity. Twenty‐nine pluriparous and 18 primiparous cows were allocated to four different feeding groups 42 days before expected parturition until 100 days postpartum and fed a ration with either a low concentrate proportion of 30% (LC) or a high concentrate proportion of 60% (HC). After parturition, all animals received 30% concentrate which was increased to 50% either within 16 (LC group) or 24 days (HC group). Half of the animals per group were supplemented with 24 g NA per day from 42 days prepartum until 24 days postpartum. All investigated parameters varied significantly over time compared to parturition (p < .05). Ferric reducing ability (FRA) exhibited a nadir before parturition, and the antioxidant enzymes glutathione peroxidase (GPX) and superoxide dismutase (SOD) showed peak activities around parturition. Expression levels of GPX1, SOD2, xanthine dehydrogenase (XDH) and nuclear factor (erythroid‐derived 2)‐like 2 (NRF2) peaked before calving. The concentrate level influenced GPX activity and mRNA abundance of SOD2, XDH and poly (ADP‐ribose) polymerase 1 (PARP1). Pluriparous animals exhibited higher serum GPX activities, a more distinct nadir for FRA and higher expression levels for GPX1, SOD2 and XDH. Primiparous cows displayed higher serum SOD activities. NA supplementation increased serum SOD activity antepartum in LC animals. Parturition was characterised by an increased need for antioxidants and an increased expression of oxidative stress‐related genes that clearly differed with parity and was influenced by energy supply while NA exerted only minor effects on the investigated parameters.     

Carcass traits and meat quality of Texel lambs raised in Brachiaria pasture and feedlot systems

Our hypothesis suggests an improvement in carcass and meat quality of pasture‐finished animals by introducing concentrate feed into diets. This study aimed to evaluate the effect of different levels of protein‐energy supplementation on carcass and meat characteristics of Texel lambs raised on Brachiaria pastures, and compare the results with those obtained from confined animals. Thirty 2‐month‐old intact lambs were divided into five treatments: pasture with mineral supplementation, pasture containing daily supplies of 0.8, 1.6, and 2.4% BW protein‐energy supplementation, and confinement (reference treatment). All animals were slaughtered 104 days after the beginning of the experiment. Lambs submitted to 1.6% and 2.4% BW supplementation presented similar characteristics to animals kept in confinement and were superior to animals treated with 0 or 0.8% of BW supplementation levels (p < .05). Increases of subcutaneous fat thickness were verified for 0.0, 0.8, 1.6, 2.4% BW, and confinement treatments, being respectively of 0.25, 0.74, 1.61, 1.69, and 1.98. Conversely, treatments had no influence on meat physical‐chemical characteristics, being all considered moderately soft, juicy (tender), and with mild tastes and odors. Lambs raised on Brachiaria pastures have high‐quality meat, but more protein‐energy supplementation is needed to be an alternative for the feedlots for young animals.     

Hepatitis E virus and related viruses in wild,domestic and zoo animals: A review

Hepatitis E is a human disease mainly characterized by acute liver illness, which is caused by infection with the hepatitis E virus (HEV). Large hepatitis E outbreaks have been described in developing countries; however, the disease is also increasingly recognized in industrialized countries. Mortality rates up to 25% have been described for pregnant women during outbreaks in developing countries. In addition, chronic disease courses could be observed in immunocompromised transplant patients. Whereas the HEV genotypes 1 and 2 are mainly confined to humans, genotypes 3 and 4 are also found in animals and can be zoonotically transmitted to humans. Domestic pig and wild boar represent the most important reservoirs for these genotypes. A distinct subtype of genotype 3 has been repeatedly detected in rabbits and a few human patients. Recently, HEV genotype 7 has been identified in dromedary camels and in an immunocompromised transplant patient. The reservoir animals get infected with HEV without showing any clinical symptoms. Besides these well‐known animal reservoirs, HEV‐specific antibodies and/or the genome of HEV or HEV‐related viruses have also been detected in many other animal species, including primates, other mammals and birds. In particular, genotypes 3 and 4 infections are documented in many domestic, wildlife and zoo animal species. In most cases, the presence of HEV in these animals can be explained by spillover infections, but a risk of virus transmission through contact with humans cannot be excluded. This review gives a general overview on the transmission pathways of HEV to humans. It particularly focuses on reported serological and molecular evidence of infections in wild, domestic and zoo animals with HEV or HEV‐related viruses. The role of these animals for transmission of HEV to humans and other animals is discussed.     

Effects of extrusion and supplementation of exogenous enzymes to diets containing Chinese storage brown rice on the carbohydrase activity in the digestive tract of piglets

Two experiments were conducted to study the effects of extrusion of Chinese storage brown rice and of exogenous enzymes supplementation to diets containing Chinese storage brown rice on the carbohydrase activity in digestive tract of piglets. In Experiment 1, 96 weaned piglets [initially 6.95 ± 0.05 kg body weight (BW)] were used in a 2 × 2 factorial design, the animals were fed the diets containing extruded Chinese storage brown rice or non‐treated Chinese storage brown rice and supplemented with or without exogenous enzymes. Each treatment had six replicate pens and four piglets in each pen. The results demonstrated that extrusion significantly increased (p < 0.05) the activity of duodenal maltase after 14 days of treatment and glucoamylase after 28 days of treatment, jejunal lactase, maltase, isomaltase, sucrase and α‐amylase after 28 days of treatment, and jejunal α‐amylase after 14 days of treatment; enzyme supplementation positively influenced (p < 0.05) the activity of pancreatic α‐amylase after 14 and 28 days of treatment, pancreatic glucoamylase after 28 days of treatment and ileal trehalase after 14 days of treatment. Similarly, interaction between extrusion and enzyme addition existed after 14 days of treatment on the activity of pancreatic α‐amylase and duodenal maltase and on the activity of duodenal glucoamylase and isomaltase, jejunal α‐amylase, lactase, maltase, isomaltase and jejunal α‐amylase after 28 days of treatment. In Experiment 2, six piglets (initially 21 ± 1.85 kg BW) fitted with ileal ‘T’‐cannulas in a 6 × 6 Latin Square Design were used to study the effects of extrusion and addition of exogenous enzymes on ileal carbohydrase activity and nutrients digestibility. The results showed that exogenous enzymes significantly (p < 0.05) increased ileal α‐amylase, glucoamylase and trehalase activity. The interaction between extrusion and enzyme supplementation had positive effect (p < 0.05) on the ileal lactase, cellobiase and sucrase activity.     

Effect of nano‐sized,elemental selenium supplement on the proteome of chicken liver

The nano‐sized (100–500 nm) selenium has higher bioavailability and relatively lower toxicity compared to other selenium forms. The objective of the present study was to compare liver proteome profiles of broiler chicken fed with control diet without Se supplementation and diet supplemented with nano‐Se with 4.25 mg/kg DM. Differential proteome analyses were performed by two‐dimensional gel electrophoresis (2D‐PAGE) followed by tryptic digestion and protein identification by liquid chromatography–mass spectrometry (LC‐MS). Seven hundred and eight spots were detected, and 18 protein spots showed significant difference in their intensity (p < 0.05) between the two groups. In response to nano‐Se supplementation, the expression of 8 proteins was higher, and 5 proteins were lower in nano‐Se supplemented group compared to control group. The functions of the differentially expressed proteins indicate that the high dose of selenium supplementation induced a dietary stress. Selenium supplementation may influence the metabolism of fatty acids and carbohydrates and antioxidant system, and increase the quantity of cytoskeletal actin and the expression of actin regulatory protein as well.