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Chromium: Pharmacological Applications in Heat-Stressed Poultry
Abstract
Heat stress has been associated with depressed growth in meat-type birds and a decline in egg production and quality in laying hens. During heat stress, feed intake tends to decrease, thus the availability of certain important minerals is reduced. Chromium (Cr) is one such mineral, which is required for maintaining growth performance in poultry due to its role in growth, metabolism and alleviation of lipid peroxidation. The available scientific literature on Cr has documented the beneficial effects of this essential mineral in improving poultry performance under conditions of environmental heat stress. In the present review, past and present information about the specific role of Cr in heat-stressed poultry is presented.
... Various techniques are also practiced to reduce heat stress in poultry (Chand et al., 2016). Such methods include the use of electric fans, cooling pad systems, and the sprinkling of water through foggers (Khan et al., 2014). As most of these methods cannot be practiced due to high expenses, other strategies such as nutritional therapies, including the use of balancing nutrient contents and the addition of vitamin C, sodium bicarbonate, potassium carbonate, and aspirin in drinking water, can be followed. ...
The present study revealed that there was a significant (P<0.05) effect of betaine on body weight, feed intake, and feed conversion ratio (FCR) of the broiler. Productive performance and blood cholesterol level of the broiler. A total of 150-day-old broiler chicks (Cobb 500) were placed into five dietary treatment groups: T0 (control diet), T1 (0.03% betaine in water), T2 (0.06% betaine in water), T3 (0.09% betaine in water), and T4 (0.12% betaine in water). Each group consisted of three replications containing 10 birds in each. Body weight gain (BWG), mortality rates, and meat yield characteristics were recorded. The collected data were analyzed by one-way ANOVA using SPSS version 25.00 software. Above, the total body weight was significantly highest in
... Several studies have used Cr supplementation as a nutritional strategy (Jahanian & Rasouli, 2015; to improve growth performance, immune response, nutrient metabolism (Oba et al., 2012), stress response and antioxidant function (Ghazi et al., 2012;Khan et al., 2014) in broilers. A pervious study demonstrated that Cr absorption increased in the presence of ascorbic acid, amino acids and a high-carbohydrate diet, while phytic acid reduced tissue and blood Cr concentrations (Hunt & Stoecker, 1996). ...
Background
Antioxidants such as vitamin C (VC) and chromium (Cr), which effectively scavenge free radicals, may improve functional characteristics of the intestine and may reduce intestinal diseases. Cr absorption increases in the presence of VC. In poultry, VC is mainly derived from glucose; hence, Cr is an important component for glucose tolerance. We evaluated the synergistic effects of these two antioxidants together.
Objectives
This study aims to investigate two levels of VC and two levels of Cr and their interaction on growth performance, carcass characteristics, digestive organs, immunity, blood constituents, liver enzymes, cecal microflora, meat sensory taste and fatty acid profile of breast meat in broilers.
Methods
Two levels of VC (250 and 500 mg/kg dry matter [DM]) and two levels of Cr (700 and 1400 μg/kg DM) were added to a basic diet for 42 days in five treatments. The 2 × 2 plus 1 (control group) factorial experiment was performed in a completely randomised design for 42 days using 360 one‐day‐old male chicks.
Results
Very low‐density lipoprotein, high‐density lipoprotein, low‐density lipoprotein, total cholesterol and triglyceride level, liver enzymes, antibody titer against sheep red blood cells, fat content, odour, chewing ability, elasticity and oral sensation traits were affected by combination of VC and Cr.
Conclusions
Combination of VC and Cr can increase unsaturated fatty acids and decrease saturated fatty acids, as well as improve cecal microbial flora, and may be useful as antioxidant compounds and non‐antimicrobial stimulants for economic growth. The use of 250 mg/kg of VC and 700 μg/kg of Cr is recommended in broiler diets.
... The GIT of chickens has diverse microenvironment with a complex population of microorganisms (Rolhion and Chassaing, 2016;Glendinning et al., 2019;Wang et al., 2023), and contributes to the host's gut homeostasis, immune status, and metabolism (Dunislawska et al., 2021). Inclusively, the intestinal microbiota plays pivotal role in nutrient digestion, growth performance, pathogen exclusion and the overall health of chickens Schokker et al., 2015;Sohail et al., 2015;Yadav and Jha, 2019;Wang et al., 2023) (Gibson and Fuller, 2000;Doyle, 2001;Khan et al., 2014;Pender et al., 2017;Amrit et al., 2021;Ayalew et al., 2022). These microbial manipulations may change the bacterial composition, influence its developmental process, enhance the immune system, and maintain GIT integrity as well as the overall health of chickens, as shown in Figure 2 (Indikova et al., 2015;Pender et al., 2017;Rajesh et al., 2020;Abd El-Hack et al., 2021;Celina and Tamiris, 2021). ...
Early embryonic exogenous feeding of bioactive substances is a topic of interest in poultry production, potentially improving gastrointestinal tract (GIT) development, stimulating immunization, and maximizing the protection capability of newly hatched chicks. However, the biophysiological actions and effects of in ovo administered bioactive substances are inconsistent or not fully understood. Thus, this paper summarizes the functional effects of bioactive substances and their interaction merits to augment GIT development, the immune system, and microbial homeostasis in newly hatched chicks. Prebiotics, probiotics, and synbiotics are potential bioactive substances that have been administered in embryonic eggs. Their biological effects are enhanced by a variety of mechanisms, including the production of antimicrobial peptides and antibiotic responses, regulation of T lymphocyte numbers and immune-related genes in either up- or downregulation fashion, and enhancement of macrophage phagocytic capacity. These actions occur directly through the interaction with immune cell receptors, stimulation of endocytosis, and phagocytosis. The underlying mechanisms of bioactive substance activity are multifaceted, enhancing GIT development, and improving both the innate and adaptive immune systems. Thus summarizing these modes of action of prebiotics, probiotics and synbiotics can result in more informed decisions and also provides baseline for further research.
... The HS has been shown to have a negative effect on testes and testicular function through inhibition of intracellular ion exchange (Ayo et al., 2011;Khan et al., 2014;Chen et al., 2015), as well as influencing the ejaculate volume, concentration and motility of sperm (Turk et al., 2016). The adverse impact of HS on performance, semen quality, and fertility of animals was observed when the air temperature was increased above 27°C (Biswas et al., 2009). ...
... However, no difference was observed in the TBARS of CTR vs. FLAXCr. Previous studies have reported antioxidant properties of Cr attenuating oxidative stress by ameliorating lipid peroxidation (Khan et al., 2014;Fraz et al., 2023). However, presence of Cr in a flaxseed-containing diet prevented the TBARS reducing effect in the serum. ...
Flaxseed is a rich source of α-linolenic acid (ALA, 18:3 n-3) and can be used to enrich chicken tissues with n-3 fatty acids (FA). However, antinutritional factors in flaxseed compromise the live performance of birds coupled with increased oxidative stress. Chromium (Cr) is a trace element with antioxidant properties. It is hypothesized that Cr supplementation will affect the hepatic total lipid profile, phospholipid n-3 and n-6 FA molecular species, lipid oxidation products, and transcription of genes associated with lipid metabolism in broiler chickens fed flaxseed. Ninety (n = 90), day-old Cornish cross chicks were fed a corn-soybean meal-based diet containing 0% flaxseed (CTR), 10% flaxseed (FLAX), and FLAX + 0.05% organic Cr (FLAXCr) for 42 d. The chicks were kept in 18 pens with 5 chicks per pen. For all response variables, the effect of dietary treatments were compared separately using SAS 9.4. P values were considered significant at ≤0.05. Total lipids, saturated FA, long-chain (≥20C) n-6 FA were reduced while total n-3 FA and long-chain n-3 FA were higher in the liver of FLAX and FLAXCr than CTR (P < 0.05). Hepatic phosphatidylcholine (PC) and phosphatidylethnolamine (PE) n-3 species (36:5, 38:6) were higher in FLAX and FLAXCr compared to CTR (P < 0.05). On the contrary, n-6 species in PC (36:4, 38:4) and PE (38:4) were lower in FLAX and FLAXCr compared to CTR (P < 0.05). Addition of Cr to a flaxseed-containing diet led to an increase in PE 36:4 (P < 0.05). A decrease in the transcription of ELOVL6 gene involved in de novo lipid synthesis was observed in FLAXCr (P = 0.01). An increase in the transcription of genes involved in FA oxidation (ACAA2, ACOX1) was observed in FLAX compared to FLAXCr (P = 0. 05; P = 0.02). A trend for a decrease in the transcription of FADS2 and HMGCS1 was observed in FLAXCr than CTR and FLAX (P = 0.06; 0.08). Transcription of other genes involved in de novo lipid synthesis (FASN, PPARA), FA oxidation (CPT1A, CPT2, ACAA1), and oxidative stress response (GPX1, NQO11, GSTA2, SLC40A1, NFE2L2) were not affected by the diets (P > 0.05). Lipid peroxidation products measured as thiobarbituric acid reactive substances (TBARS) in liver was reduced in FLAXCr than CTR (P < 0.05) and was not different from FLAX (P > 0.05). Serum cholesterol and aspartic aminotransferase were reduced in FLAX and FLAXCr compared to CTR (P < 0.05). The serum glucose level was decreased in FLAX compared to CTR (P < 0.05) and a trend in decrease was noticed in FLAXCr vs. CTR (P = 0.10). Serum TBARS were higher in CTR and FLAXCr compared to FLAX (P < 0.05). In conclusion, flaxseed supplementation enhances total and long-chain n-3 FA while reducing total lipids, saturated, and n-6 FA in the liver. Supplementing Cr along with flaxseed increased n-6 FA species in the hepatic PE and decreased the transcription of genes involved in FA oxidation and lipid synthesis.
... The growth and productive performance are greatly affected by the high ambient temperature and relative humidity (Khan et al. 2014). The deleterious effects of high ambient temperature are more when combined with humidity (Ajakaiye et al. 2011). ...
The present study aimed to investigate the effects of vitamin C supplementation on stress and antioxidative status of sixty 26 weeks old commercial layer birds during summer in Mizoram. Two groups of birds were reared for a period of 2 months, viz. control group and VC. Control group was on basal diet @120 g/bird/day while VC was supplemented with vitamin C @ 250 mg/kg basal diet. THI was calculated from the records of AT and RH during the period. Blood samples were collected from wing vein of each bird on 0, 30th and 60th day of treatment for estimation of HSP70, H:L, SOD, GPx, CAT, TBARS, FRAP, blood glucose, total plasma protein, total protein of hemolysate and total cholesterol. The THI recorded during the period of study was not indicative of heat stress while Tmax of 30ºC and RHmax of 95% were above the optimal ranges for poultry. Presence of heat stress and decrease in antioxidative status of control group was detected by increase in HSP70, SOD, GPx, CAT, TBARS and total cholesterol and decrease in FRAP, total plasma protein and total protein of hemolysate. Upon vitamin C supplementation, HSP70, GPx and TBARS became stable, SOD and CAT activity and total cholesterol decreased and FRAP, total plasma protein, and total protein of hemolysate increased. The estimates of heat stress and antioxidative markers indicated presence of stress in commercial layers in summer and vitamin C supplementation was found to ameliorate the stress and improve the antioxidative status.
An experiment was carried out to assess the efficacy of supplemental ascorbic acid (AA) on broiler chicken production performance, blood haematological profile, biochemical profile, and carcass traits under heat stress conditions. A total of 192-day-old broiler chicks were divided into four groups, each with six replicates of eight each (4 × 6 × 8). Four corn-based dietary treatments were formulated: T1 (control diet), T2 (T1 + AA at 200 mg/kg), T3 (T1 + AA at 400 mg/kg), and T4 (T1 + AA at 600 mg/kg) for a period of 42 days. Despite the high temperature and humidity, the 600 mg AA supplemental groups (T4) gained significantly (P ≤ 0.05) more body weight and had a higher feed intake and better feed conversion ratio (FCR) than the control group (T1). After 28 days of feeding the three AA-supplemented diets, antibody titres (humoral immune response) were significantly higher (P ≤ 0.05). The response to intradermally injected phyto-haemagglutinin (PHA-P), an index of the in vivo cell-mediated immune response, was found to be increased (P ≤ 0.05) in the 400 and 600 mg AA-supplemented groups after 35 days. Higher levels of AA (T4) supplementation significantly (P ≤ 0.05) improved haematological values such as haemoglobin (Hb), total erythrocyte count (TEC), total leukocyte count (TLC), and differential leukocyte count (DLC), heterophil:lymphocyte (H:L) in comparison to the control group (T1). The supplemented group improved the serum biochemical profile of the birds, with an increase (P ≤ 0.05) in total serum protein, albumin, and globulin and a decrease in serum cholesterol and corticosterone levels in the T4 group compared to the control group. Heat shock protein-70 (HSP-70) was gradually elevated after increasing the ascorbic acid concentration (P ≤ 0.05) at 14 and 21 days. As a result, it can be concluded that supplementing ascorbic acid at 600 mg/kg is beneficial for improving the performance, immunity, and blood haematological biochemical profile and upregulating the HSP-70 gene of broiler chickens under heat stress conditions.
Heat stress is a threat that can lead to significant financial losses in the production of poultry in the world’s tropical and arid regions. The degree of heat stress (mild, moderate, severe) experienced by poultry depends mainly on thermal radiation, humidity, the animal’s thermoregulatory ability, metabolic rate, age, intensity, and duration of the heat stress. Contemporary commercial broiler chickens have a rapid metabolism, which makes them produce higher heat and be prone to heat stress. The negative effect of heat stress on poultry birds’ physiology, health, production, welfare, and behaviors are reviewed in detail in this work. The appropriate mitigation strategies for heat stress in poultry are equally explored in this review. Interestingly, each of these strategies finds its applicability at different stages of a poultry’s lifecycle. For instance, gene mapping prior to breeding and genetic selection during breeding are promising tools for developing heat-resistant breeds. Thermal conditioning during embryonic development or early life enhances the ability of birds to tolerate heat during their adult life. Nutritional management such as dietary manipulations, nighttime feeding, and wet feeding often, applied with timely and effective correction of environmental conditions have been proven to ameliorate the effect of heat stress in chicks and adult birds. As long as the climatic crises persist, heat stress may continue to require considerable attention; thus, it is imperative to explore the current happenings and pay attention to the future trajectory of heat stress effects on poultry production.
Any practice which results in broiler carcass fat reduction will benefit the poultry industry. Because the trace minerals chromium and manganese have both been implicated in lipid and carbohydrate metabolism, this study was conducted to investigate the effects of supplemental chromium picolinate (CrPic) or manganese proteinate (MnPro) on performance of heat-distressed broiler chickens. Dietary CrPic supplementation increased total gain and feed efficiency. Birds fed 240 mg/kg Mn had a higher percentage of abdominal fat pad (AFP) when housed under heat stress (HS), but lower AFP in a thermoneutral (TN) environment. This response was the reverse of the control group, for which heat stress conditions reduced gain and feed intake, increased feed efficiency, decreased abdominal fat, and increased percentage yield of carcass, breast, and leg. Based on these results, CrPic supplementation under HS or TN improves live performance and few carcass characteristics. Further, a high level of MnPro supplementation appears to be beneficial under TN conditions. Certainly, additional studies are required.
A substantial growth in poultry industry has been observed mainly due to exploitation of various modern growth promoting strategies and appropriate disease preventive and control measures. The present review describes the various essential growth promoters and novel feed supplements, their salient features, classical examples, bioactive principles, pharmacological and modes of action, and useful applications for improving poultry production and health. It highlights antibiotics, probiotics, prebiotics, synbiotics, organic acids, vitamins and minerals, oils, enzymes, amino acids, betaine, carnitine, L-arginine, ractopamine, nucleotides, electrolytes, herbs, panchgavya elements. Apart from boosting poultry production and safeguarding general health of birds some of these have been found to possess beneficial immunomodulatory and stress relieving properties, and also have added advantages to help produce lean meat and designer poultry products taking into account health awareness and preferences of the consumers. It is a comprehensive and an updated review compilation focusing the salient aspects of various important growth promoters and feed additives having potential applications to promote poultry production and health. Due care has been taken to cover the ongoing trends and recent advances with a perspective vision and their holistic usages and beneficial applications in poultry production system. The contents of the review will be highly useful for researchers, scientists, pharmacists, veterinary professionals, pharmaceutical industries, poultry producers / owners and poultry industry as well as for perspective applications in livestock industry. It would enrich the knowledge of researchers and help the scientific community to conduct more research on such daily essential requirements for boosting poultry production in a better way. It will also shed light regarding the management and production aspects of poultry especially broilers which will enlighten farmers and poultry producers for better economic growth.
In this review, perspective roles and applications of molecular tools and techniques boosting production
potentials and protection from economically important diseases are discussed. Importance of advent in genetic engineering, designer products, disease resistant plants and animals, advanced diagnostics, networking programmes, effective and safer vaccines as well as novel and emerging therapies are highlights of the review. The production of designer foods along with progress in ‘Omics’ as well as analytical fields contributed immensely for safeguarding health of livestock. For plunging losses caused to plant and animal population from pathogens, numerous methods are being adopted by biologists for engineering resistant breeds of animals and plants during last two decades. Advancements have been made in development of innovative detection methods (including modification of polymerase chain reaction) which have contributed in clinical decision making procedures and to determine the molecular epidemiology. Several new generation vaccines viz. DNA vaccines, reverse genetics vaccines, vector
based vaccines, protein or peptide-based vaccines, gene-deleted vaccines and chimeric vaccines etc. have been developed or are under developmental phase for combating a wide array of diseases. Mapping for location of herds and flocks, enrichment of knowledge of epidemiologists and diagnosticians, clinicians along with researchers has become possible with the advancement of geographical information system (GIS). In addition bacteriophage, virophage, cytokine, probiotics as well as herbal, nutritional, immunomodulation therapy and cow (panchgavya) therapy have proved to be beneficial. Among them many are cost-effective and cause only minimal adverse reactions. This review gives a brief presentation of all the important innovative technologies boosting production and safeguarding health of humans and animals.
There are ongoing trends ofimmunomodulation to combat a vast range of human and animal diseases including the incurable diseases like viral diseases, cancers, autoimmune diseases and inflammatory conditions. Animate as well as non-animate factors, surrounding us are interacting with our immune system. A balanced diet should contain all essential components from energy to vitamin and trace minerals. Each of these constituent has a very special effect on the immune system starting from their development to active role in immunity therefore, the outcome of their deficiency often ends in disease. Edible items which we consume like various vegetables, spices, herbs, fruits etc., are also equally responsible in manipulation of our system either in positive or negative way. Water has biggest share in our body and acts as the main medium to support the activities of the different system of body without exception of immune system. Proper environmental temperature is essential to maintain body's functions and experiments carried out regarding the effect of temperature suggest that extremes of the temperature are often cause immunosuppression directly by acting on the cells of immunity or indirectly through inducing stress and thereby increasing production of catecholamine which are potent anti-immune molecules. Various pathogenic as well as non-pathogenic bacteria cause immune suppression and immune potentiation, respectively. Proper exercise hold a prime position in the healthy life as it supports immunity and keeps disease away. The present review deals with all these immunomodulators having both positive and negative impact on the health status of an individual.
At present, almost every third person in the society is under stress and having chronic disorders like diabetes, arthritis, allergy, cardiovascular disease, fatigue and even cancer. Recently, there is decline in the physical and mental capabilities along with the social values. So this certainly should raise the alarms as to why such deterioration is taking place in the society or what are the changes in the lifestyle that might have a role direct/indirect in evolution of such changes? Vegetable is an immense store of active chemical compounds and considered as the cheapest and most easily available sources of carbohydrate, fiber, proteins, vitamins, minerals and amino acids. The intake of green and leafy vegetables lowers the risk of chronic diseases, cardiovascular diseases, anemia, cancer, oxidative stress, diabetes, weight gain etc. In recent time, vegetables have also been identified as safe and economic expression system for producing the recombinant proteins including the vaccines against many infectious diseases like hepatitis B, malaria, rotavirus, HIV, Helicobacter pylori, pestedes petits ruminants etc. However, besides the beneficial effect, contaminated and raw vegetables harbors pesticide residues and many pathogenic microbes viz., norovirus, Salmonella, E. coli, Shigella, Listeria monocytogens and also prove to be an excellent source of disease outbreaks. The present review highlights the phytonutrients and neutraceuticals in fruits and vegetables; their medicinal and health benefits for humans and their domestic as well as companion animals along with their fruitful practical applications and perspectives like bioreactor for producing vaccine along with the methods that can increase their nutritional benefits.
Modern medicine has helped to a great extent to eradicate and cure several diseases of mankind and animals. But the existence of incurable diseases like cancer, Acquired Immunodeficiency Syndrome (AIDS), diabetes or rheumatoid arthritis, side effects of allopathic medicine, increasing trend of antibiotic resistance and chemicals and biopesticides causing dietary risk have made the situation more critical than ever before. Thus, it has become a matter of concern for the scientists and researchers to develop novel therapies. Bacteriophage therapy to treat pathogenic bacterial infections, virophage therapy for conservation of global system and avian egg yolk antibody therapy for designing prophylactic strategies against Gastrointestinal (GI) diseases are interesting approaches. Others include the use of cytokines as adjunctive immunomodulators, gene therapy focusing on diseases caused by single gene defects, RNAi technology to suppress specific gene of interest and apoptins for cancer treatment. Stem cell therapy against several diseases and ailments has also been discussed. The use of nanoparticles for better drug delivery, even though costly, has been given equal importance. Nevertheless, immunomodulation, be it through physiological, chemical or microbial products, or through essential micronutrients, probiotics, herbs or cow therapy prove to be cost-effective, causing minimum adverse reactions when compared to allopathy. Development in the field of molecular biology has created an enormous impact on vaccine development. The present review deals with all these novel and emerging therapies essential to safeguard the health of humans and companion animals.
Herbs/Botanical plants are considered as God's gift to human beings in the form of natural medicines, like the one well known "Sanjeevani booti" described in Hindu Mythology. The traditional and ethno-veterinary practices have been in use for centuries, transferring the knowledge from generation to generation and they are accessible, easy to prepare and administer, with little or no cost at all. Even though the modern developments in therapeutic field brought about a rapid decline in traditional medicine, the plant-based remedies are still having a crucial role as potential source of therapeutic aids in health systems all over the world for both humans and animals. Among the 21,000 medicinal plants listed by the World Health Organization (WHO), 2500 species are native to India, which stands first in the production of medicinal herbs. This innumerable treasure of medicinal herbs brings India the distinction of 'the botanical garden of the world'. Nowadays immune-based therapies are gaining more importance than monovalent approaches which are having limited benefits. Apart from the actions like treating diseases, control of ecto- and endo-parasites, fertility enhancement, bone setting and poor mothering management, an array of herbal medicines have been reported which are having immunomodulatory effects like modulation of cytokine secretion, histamine release, immunoglobulin secretion, class switching, cellular co-receptor expression, lymphocyte expression, phagocytosis and so on. The present article describes in brief few of these important ones viz., ashwagandha, amla, tulsi, arjuna, aloe vera, garlic, turmeric, ginger, shatavari, neem, guduchi, kiwifruit, tut, kamala, palashlata, kokilaksha etc. being used for human and animal health benefits.
Avian spermatozoa are characterised by high proportions of polyunsaturated fatty acids (PUFAs) which is associated with increased susceptibility to reactive oxygen species (ROS) and lipid peroxidation. Recent advances in avian reproduction have focused on the potential of ROS as one of the prime mediators of infertility. Although ROS are involved in many physiological functions of spermatozoa, their excessive production may result in oxidative stress. The production of ROS is enhanced during unfavourable environmental and stressful conditions, and an effective scavenging system is essential to counter the production of ROS. Antioxidants are compounds that suppress the formation of ROS. Enzymatic and non-enzymatic antioxidants build a powerful antioxidant system in avian semen which is able to protect it against ROS and lipid peroxidation. The balance between ROS and antioxidants in avian semen is a fundamental determinant of membrane integrity, sperm viability and fertilising ability. A regulating role of ROS in sperm function in mammalian sperm along with their counteractive mechanisms have been extensively studied; but their role for avian species reproduction remains to be elucidated. Various antioxidants belonging both to enzymatic and non-enzymatic groups can counter oxidative stress. Hence the rationale of using antioxidants is advocated.
Two hundred and eighty-eight 21-week-old Hyline Brown laying hens were randomly allotted to 9 treatments, 32 birds for each treatment. A 33 (chromiumL-carnitine) factorial experiment was designed to investigate the single and interactive effects of adding yeast chromium (0, 400 and 600 g/kg) and L-carnitine (0, 50 and 100 mg/kg) to corn-soybean diets on lipid metabolism of laying hens for 7 weeks. The results showed that 600 g/kg chromium or 100 mg/kg L-carnitine had significant effects on most indices of lipid metabolism (p
Diets for broiler chickens (n=90) were supplemented with chromium (CrCl3, 6H2O), either alone (0·2 mg/kg diet) or in a combination with ascorbic acid (0·2 mg Cr and 50 mg ascorbic acid/kg diet). The objectives of the study were to ascertain if ascorbic acid had any additive effect on the actions of chromium and whether chromium supplementation could alleviate the nutritional stress in the birds imposed by a reduced energy intake. The birds were fed at the recommended (Bureau of Indian Standards 1992) and at a lower plane of energy. Live-weight gain and diet utilization were higher (P<0·01) when the normal energy diet supplemented with chromium was fed. Food intake (35 days) was higher (P<0·001) in the birds fed with the low energy diet. There was an increase (P<0·01) in metabolizability due to the supplementation of chromium. The metabolizability of crude protein and total carbohydrate increased (P<0·05) when chromium and ascorbic acid were supplemented together. Chromium intake was higher (P<0·001) in the supplemented birds, especially in those fed with the low energy diet (P<0·05), though its retention was higher (P<0·05) when the normal energy diet was given. Chromium in combination with ascorbic acid also enhanced (P<0·01) chromium retention. Blood glucose (P<0·001) and plasma cholesterol (P<0·05) were lower in the supplemented birds and blood glucose was reduced further when ascorbic acid was supplemented together with chromium (P<0·01). Plasma protein increased (P<0·05) in the supplemented chickens. However, variation in the dietary energy concentration did not exert any significant effect on these blood parameters. Plasma chromium was higher (P<0·05) in the supplemented birds, though chromium had little effect in this regard with ascorbic acid. Plasma copper increased (P<0·05) when chromium was supplemented alone and increased further (P<0·05) when chromium and ascorbic acid were supplemented together. Deposition of chromium in the breast and thighs increased (P<0·05) due to supplementation. Protein content and total accretion of protein in the carcass were higher (P<0·05) when chromium was supplemented alone and with ascorbic acid. The supplemented birds had less (P<0·01) fat per 100 g of carcass irrespective of the dietary energy concentration. Weight of the hot carcass increased (P<0·05) due to chromium supplementation although dietary energy concentration did not affect this particular parameter. It was concluded that inorganic chromium supplementation (0·2 mg chromium/kg diet) might effectively enhance the growth performance, diet utilization and carcass characteristics in broiler chickens. Addition of ascorbic acid might also be beneficial in this regard. However, dietary energy concentration was more critical and to yield the maximum benefit of Cr supplementation in broiler chickens, an optimum level was essential.