***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: This study was conducted to determine the effects of dietary supplementation with Cr nicotinate and Cr chloride and their optimum inclusion rate on performance , carcass traits , meat oxidative stability , serum metabolites , hematological parameters , and liver chromium concentration in heat-stressed broilers . A total number of 420 , 1-day-old male broiler chicks were r and omly assigned to seven treatments with four replicates of 15 chicks . The dietary treatments consisted of the basal diet supplemented with 0 ( control ) , 500 , 1,000 , and 1,500 μg/kg Cr in the form of Cr nicotinate and Cr chloride .  Chicks were raised for 6 weeks in heat stress condition ( 33 ± 2 ° C ) . Supplements of organic and inorganic Cr particularly at 1,500 μg/kg incorporation increased feed consumption ( P < 0.05 ) and body mass gain of broilers ( P < 0.01 ) . Cr supplementation increased carcass yield and decreased abdominal fat  ( P < 0.01 ) . Supplementation of 1,500 μg/kg Cr nicotinate ( P < 0.05  ) enhanced liver Cr concentration . Storage time increased lipid oxidation of meat  ( P < 0.01 ) . Cr decreased lipid oxidation of breast and thigh muscles over 2 ( P < 0.01 ) or 6 ( P < 0.05 ) days of storage time . Birds fed 1,500 μg/kg Cr nicotinate , had lower concentration of serum glucose and triglyceride at 21 days ( P < 0.05 ) . Hematological parameters tested at 21 and 42 days , were not influenced . The results suggested that dietary Cr supplementation regardless of its source have a positive effect on productive , and carcass traits , also enhances oxidative stability of refrigerated meat in broilers reared under heat stress conditions The aim of this study was to investigate the effect of dietary supplementation of nanoparticle trivalent chromium on nutrient utilization , growth performance and serum traits of broilers . This study included two trials . In trial 1 , 32 three-week-old broilers were divided into four groups : the control , chromium chloride ( CrCl3 ) , chromium picolinate ( CrPic ) and nanoparticle chromium picolinate ( NanoCrPic ) . Chromium was added at a 1200 μg/kg level to evaluate the nutrient and chromium utilization . In trial 2 , 160 one-day-old broilers were r and omly divided into four groups as in trial 1 , with four replicates . The results of trial 1 indicated that the chromium utilization is as follows : NanoCrPic > CrPic > CrCl3 and control groups , with significant differences between groups ( p < 0.05 ) . Crude fat utilization in CrCl3 group was lower than in that the control group ( p < 0.05 ) . The results of trial 2 indicated that feed intake of 4 - 5 weeks showed better result in the CrCl3 group than that in the CrPic group ( p < 0.05 ) . The results of serum traits indicated that the LDL-cholesterol in the NanoCrPic groups was lower than that in the CrPic group ( p < 0.05 ) . The NanoCrpic and CrPic groups showed significantly increased serum chromium concentration when compared with the control and CrCl3 groups ; the triglyceride level in the CrCl3 group was lower than that in the CrPic group ( p < 0.05 ) . This study concluded that compared with CrPic , NanoCrpic supplementation could increase chromium utilization and lower the serum LDL-cholesterol of broilers The effects of 8 wk of daily chromium supplementation ( 3.3 - 3.5 mumol as chromium chloride or chromium picolinate ) or placebo ( 0.1 mumol Cr ) and weight training were examined in 36 men in a double-blind design .  Strength , mesomorphy , fat-free mass , and muscle mass increased with resistance training independently of chromium supplementation ( P < 0.0001 ) . Protein , magnesium , zinc , copper , and iron intakes equalled or exceeded the recommended dietary allowance ( RDA ) or estimated safe and adequate daily dietary intake ( ESADDI ) during training and did not change significantly from pretraining intakes ( P > 0.05 ) . Chromium supplementation increased the serum chromium concentration and urinary chromium excretion without a difference as a result of the chemical form of chromium ( P < 0.05 ) . Resistance training was associated with a significant decrease ( P < 0.05 ) in serum ferritin , total-iron-binding capacity , transferrin saturation , the ratio of enzymatic to immunoreactive ceruloplasmin , and plasma copper , independently of chromium supplementation . However , transferrin saturation was decreased more with chromium picolinate supplementation ( 24 % ) than with chromium chloride or placebo ( 10 - 13 % ) . Compared with pretraining values , urinary magnesium excretion increased ( P < 0.05 ) and urinary zinc output tended to decrease during the first 4 wk of resistance training and then returned to baseline values for the final 4 wk , which suggests an adaptation in mineral excretion in response to weight training . These findings suggest that routine chromium supplementation has no beneficial effects on body- composition change or strength gain  in men . Whether chromium supplementation of individuals with diminished chromium nutriture facilitates propitious changes in body structure and function remains to be determined 1 . This study investigated the effects of supplemental copper and chromium on the serum and egg traits of laying hens using 144 forty-five-week-old White Leghorn layers . The hens were r and omly assigned into 9 groups to conduct this 3 copper ( 0 , 125 and 250 mg/kg as copper sulphate ) × 3 chromium ( 0 , 800 and 1600 µg/kg as chromium picolinate ) factorial trial . 2 . Egg yolk cholesterol was significantly reduced by supplementary copper ( Cu ) and chromium ( Cr ) and there was an interaction between Cu and Cr supplementation . Egg production , egg weight , eggshell strength and eggshell thickness were not influenced by Cu or Cr supplementation . 3 . Serum cholesterol concentration was decreased by Cu supplementation and very low-density lipoprotein ( VLDL ) was reduced markedly by both Cu and Cr . On the other h and , high-density lipoprotein ( HDL ) was significantly increased by Cu and Cr . Interaction occurred between Cu and Cr in the VLDL and HDL parameters . Supplmentary Cu also reduced VLDL-cholesterol ( VLDL-C ) and enhanced HDL-cholesterol ( HDL-C ) , while supplemental Cr had a contrary effect on these two parameters . 4 . If minimum egg cholesterol content is the criterion , this study suggests that 125 mg/kg of Cu together with 800 to 1600 µg/kg of Cr provide adequate supplementary concentrations for laying hens 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 r and omized design . Seven hundred 1-d-old birds were r and omly 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 In this study , the effect of the supplemental organic chromium ( Cr ) forms on the expression of ovarian orexin(hypocretin ) , glucose transporters ( GLUTs ) , heat shock proteins ( HSPs ) and nuclear factor-kappaB (NF-κB)were investigated in laying hens ( HS ) . Laying hens ( n=1800 ; 16-wk-old ; Lohmann LSL-Lite ) were allocated to 6 r and om groups according to a 2 × 3 factorial trial scheme with two different environmental temperatures [ Thermoneutral ( TN groups ; at either 22±2 ° C 24 h/d ) and heat stress ( HS groups ; at 34±2 ° C for 8 h/d , 08:00 to 17:00 h , followed by 22 ° C for 16 h for a period of 12 wks ) ] , and hens reared under both environmental conditions were fed either a basal diet or the basal diet supplemented with 1.600 mg of chromium-picolinate ( CrPic , 12.43 % Cr ) and 0.788 mg of chromium-histidinate ( CrHis , 25.22 % Cr ) per kg of diet , delivering 200 µg elemental Cr per kg diet . HS groups showed decreased levels of orexin and GLUTs(GLUT1 , GLUT4 ) , and increased NFκB , HSP60 , HSP70 and HSP90 levels compared to the TN groups in ovarian tissue of hens ( P < 0.0001 for all).However , dietary chromium supplementation ( CrPic-CrHis ) increasedorexin and GLUTs levels and significantly reduced the NF-κB and HSPs levels making them closer to those of thermoneutral group ( P < 0.0001).In conclusion , CrPic and CrHis showed supported the relief and treatment of stress complications This study was conducted to investigate the effects of chromium from chromium propionate ( CrPro ) on serum lipids , carcass traits , and breast meat quality in heat-stressed birds . A total of 210 1-day-old male broilers were r and omly allotted by initial body weight ( BW ) into 5 treatments with 7 replicates with 6 birds per replicate pen for 42 days . The treatments included a basal corn-soybean meal diet and basal diet supplemented with 0.2 , 0.4 , 0.8 , or 1.6 mg Cr/kg diet . Birds had ad libitum access to feed and distilled-deionized water at normal conditions for 1–3 weeks with little or no stress , and then birds were housed under heat stress conditions with 35 ± 2 ° C ambient temperature for 4–6 weeks . Results showed that serum triglyceride ( TG ) ( P = 0.0006 ) and low-density lipoprotein cholesterol ( LDLC ) ( P = 0.0038 ) concentrations were decreased linearly as Cr dose increased . Compared with other groups , birds receiving 0.8 or 1.6 mg Cr/kg had lower TG ( P = 0.0015 ) . Compared to control birds , birds fed diets with 0.2 , 0.4 , 0.8 , or 1.6 mg Cr/kg supplementation had lower LDLC ( P = 0.0006 ) . However , the total cholesterol ( TC ) and high density lipoprotein cholesterol ( HDLC ) concentrations in serum were not affected by treatment ( P > 0.05 ) . No difference was observed in BW , the relative weights of breast muscle , thigh muscle and abdominal fat ( P > 0.05 ) , and breast meat quality ( Ph15min , Ph24h , L * , a * , b * , cooking loss , shear force ) among the treatments ( P > 0.05 ) . Results from this study indicated that CrPro supplementation could be beneficial to serum lipids metabolism of heat-stressed broiler chickens by decreasing TG and LDLC contents , but had no impacts on meat quality and carcass traits of the heat-stressed broilers A total of 250 broilers in a completely r and omized design selected to evaluate the effect of different levels of chromium ( Cr ) supplementation on performance , carcass traits and some blood parameters of heat-stressed broiler chicks . All birds were kept under heat stress temperature ( 33 ± 3 ° C ) and divided into five treatments groups . Each treatment consisted of five pens with 10 birds in each pen . The basal diets were supplemented with 0 ppb ( control ) , 800 ppb Cr-L-Met ( T1 ) , 1,200 ppb Cr-L-Met ( T2 ) or 800 ppb CrCl3 ( T3 ) , and 1,200 ppb CrCl3 ( T4 ) . The feed intake and body mass were 
    Output:
    
With the exception of studies on cold-stressed laying hens , the results of studies of Cr supplementation of chickens , whether broilers or laying hens , were found to be too inconsistent for any firm conclusions to be drawn other than that Cr supplementation generally leads to accumulation of Cr in tissues .
Few potential trends in terms or beneficial or deleterious effects from Cr supplementation were found regardless of strain of chicken , Cr source , Cr dose , duration of supplementation , or variable examined .