The nature of the nutritional importance of serum albumin to Glossina morsitans

The nutritional significance of albumin protein and its constituent amino acids or associated impurities to Glossina morsitans was evaluated. Flies fed serum-free or albumin-free diets or diets containing delipidated serum or delipidated albumin failed to reproduce. The sizes of offspring produced by flies fed on diets containing different commercial albumins varied in proportion to the amount of bound lipid present in the albumin. FLies fed on albumin-containing diets supplemented with serum lipoproteins produced heavier offspring than flies fed on unsupplemented diets or on diets supplemented by other serum proteins. Delipidation of serum lipoproteins abolished this supplementary effect suggesting a possible similarity between lipoprotein-associated and albumin-bound lipid in terms of their importance to the nutrition and reproduction of tsetse. It is concluded that the observed nutritional importance of albumin to tsetse flies may derive from albumin-associated substances rather than albumin per se.     

Dynamics of follicle development and lipid storage in the tsetse fly Glossina palpalis palpalis fed on serum albumin deficient diets

Females of Glossina p. palpalis were fed on a mixture of bovine erythrocytes and a serum substitute which had been lyophilized, for a period of 30 days. The rate of ovarian development and lipid incorporation and the fatty acid composition of whole flies were examined at five-day intervals. Results showed that in flies fed serum albumin-deficient diets, ovarian development was seriously impaired and ovulation did not take place. Flies which were fed on a serum albumin-containing diet ovulated and produced larvae, though at a lower rate than control flies. Compared with controls, lipid incorporation was reduced in experimental flies, but more in the albumin-deficient group than in the albumin-containing group. The diet composition had no marked influence on the relative composition of fatty acids in any one group. It is concluded that, though an essential nutritional element for cow blood fed G. p. palpalis, serum albumin was not the only missing essential factor in the diets that were used in this study.     

Digestive processes of haematophagous insects: control of trypsin secretion in Glossina morsitans

Glossina morsitans females were fed upon goats or components of beef blood through an Agar/Parafilm membrane and for each fly the following were determined: fly weight, meal weight, posterior midgut trypsin, posterior midgut protein, anterior midgut trypsin, and anterior midgut protein. Secretion of trypsin was stimulated by feeding flies upon goats, defibrinated beef blood, beef serum, haemolysed beef erythrocytes but not washed beef erythrocytes. There was a significant correlation between posterior midgut trypsin and the amount of protein in the posterior midgut, and the slope of the regression of trypsin upon protein content was significantly different from zero. There was a significant correlation between posterior midgut trypsin and meal size for flies 0 to 24 hr after emergence, but not those 24 to 48 hr old when fed upon a goat. For unfed flies there was a significant correlation between posterior midgut trypsin and fly weight.     

Growth performance, haematology and serum biochemistry of African catfish (Clarias gariepinus) fingerlings fed graded levels of dietary fumonisin B1

Fingerlings of Clarias gariepinus were used to evaluate the effect of dietary fumonisin B₁ (FB₁), a mycotoxin produced by Fusarium verticillioides, on growth, haematological and serum biochemical parameters. The fingerlings were sorted, weighed and randomly stocked in 16 plastic tanks at the rate of 20 fingerlings per tank. Fusarium-cultured maize grains containing FB₁ were used to formulate three diets containing approximately 5.0, 10.0 and 15.0 mg FB₁/kg, constituting diets 2, 3, and 4 respectively. These three diets, plus diet 1, which contained non-Fusarium cultured maize grains that served as the control, were used in a 6-week feeding trial. The final weight gains by the fingerlings were significantly (P?<?0.05) influenced by FB₁. The final weights of the fingerlings fed diets 2, 3 and 4 ranged from 70.07 to 87.10% of the controls. The haematocrit, erythrocytes, haemoglobin, mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and the serum protein constituents (total protein, albumin and globulin) values significantly (P?<?0.05) decreased, while the leucocytes, MCV and MCH increased significantly (P?<?0.05) with increase in the dietary FB₁. The total serum protein values of the fingerlings fed diets 2, 3 and 4 were 34.53, 39.42 and 50.17% lower than the total serum protein values of those fed the control diet. These results indicate that Fusarium-contaminated diets containing about 5.0 mg or more FB₁/kg reduced weight gain and significantly altered haematological parameters and serum protein constituents in the fingerlings. These may have a significant impact on physiological activities and may be vital in immunosuppression in the fingerlings with a strong negative impact on subsequent performance of the fish.     

Cholesterol as a limiting factor in the growth of Mycoplasma pneumoniae.

Ultracentrifugation was used to separate three commercial lots of bovine serum fraction (BSF) into components designed to contain lipoproteins. Each BSF lot and component was tested for ability to support the growth of tree strains of Mycoplasma pneumoniae. In general, the level of growth-promoting activity corresponded to the amount of cholesterol present in the BSF or BSF components rather than to the amount or type of lipoprotein Cholesterol was the limiting nutritional factor of BSF with low growth-promoting activity. The addition of cholesterol and bovine serum albumin to BSF with low activity resulted in growth equal to or greater than that observed for BSF with high growth-promoting activity. When cholesterol was added to agar medium containing BSF of low activity, mycoplasma colonies were greater in number, possessed larger mean diameters, and had centers that were more distinct than those observed when this BSF was used alone. Variability in growth-promoting actions of commercial lots of BSF was eliminated by increasing their cholesterol content to an optimum level. An adjustment of the cholesterol and albumin levels of any serum product used in culture media may provide a simple convenient method to improve growth and isolation of mycoplasmas.     

Zinc deficiency and the activities of lipoprotein lipase in plasma and tissues of rats force-fed diets with coconut oil or fish oil

The present study was performed to investigate the effect of zinc deficiency on the activities of lipoprotein lipase in postheparin serum and tissues of rats fed diets containing either coconut oil or fish oil as dietary fat, using a bifactorial experimental design. To ensure an adequate food intake, all the rats were force-fed by gastric tube. Experimental diets contained either 0.8 mg zinc/kg (zinc-deficient diets) or 40 mg zinc/kg (zinc-adequate diets). The effects of zinc deficiency on the activities of lipoprotein lipase in postheparin serum and postprandial triglyceride concentrations and distribution of apolipoproteins in serum lipoproteins depended on the type of dietary fat. Zinc-deficient rats fed the coconut oil diet exhibited a reduced activity of lipoprotein lipase in postheparin serum and adipose tissue, markedly increased concentrations of triglycerides in serum, and a markedly reduced content of apolipoprotein C in triglyceride-rich lipoproteins and high density lipoproteins compared with zinc-adequate rats fed coconut oil. By contrast, zinc-deficient rats fed the fish oil diet did not exhibit reduced activities of lipoprotein lipase in postheparin serum and adipose tissue and increased concentrations of serum lipids compared with zinc-adequate rats fed the fish oil diet. This study suggests that a reduced activity of lipoprotein lipase might contribute to increased postprandial concentrations of serum triglycerides observed in zinc-deficient animals. However, it also demonstrates that the effects of zinc deficiency on lipoprotein metabolism are influenced by dietary fatty acids.     

Solidifying agent and processing of blood used for the larval diet affect screwworm (Diptera: Calliphoridae) life-history parameters

Spray-dried whole bovine blood and a sodium polyacrylate polymer gel as a bulking and solidifying agent are among the constituents of the current larval diet for mass rearing screwworm, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae). Locally available, inexpensive dietary materials could reduce rearing cost and address an uncertain commercial supply of spray-dried blood. We compared efficacy of diet prepared from fresh bovine blood after decoagulation with sodium citrate or ethylenediaminetetraacetic acid (EDTA) or after mechanical defibrination, with the diet containing spray-dried blood using either gel or cellulose fiber as the bulking and solidifying agent. Several life-history parameters were compared among insects reared on each of the blood and bulking agent diets combination. Diets containing citrated blood yielded the lightest larval and pupal weights and fewest pupae. EDTA-treated blood with the gel also caused reductions. EDTA-treated blood with fiber yielded screwworms that were heavier and more numerous than those from the diet with citrated blood but lighter than those from the control diet using spray-dried blood. A reduction in percentage of adults emerging from pupae occurred from diets with both bulking agents using citrated blood and the diet using EDTA mixed with the gel bulking agent. As a group, the cellulose-fiber diets performed better than the gel diets. Larval diet did not affect adult longevity, weight of the eggs deposited by the females that emerged or subsequent egg hatch. Parameter measurements of insects from both defibrinated blood diets were similar to those from the spray-dried blood diets, indicating that fresh, defibrinated bovine blood can successfully replace the dry blood in the screwworm rearing medium.     

Dietary supplementation of organic or inorganic chromium modulates the immune responses of broilers vaccinated with Avian Influenza virus vaccine

Dietary supplementation with the organic chromium (Cr) has been shown to positively affect the immune function of poultry. However, to our knowledge, no experiment has been done to directly compare the impacts of Cr chloride and chromium picolinate (CrPic) on the immune responses of broilers vaccinated with Avian Influenza (AI) virus vaccine. Therefore, the present experiment was conducted to investigate the effects of supplemental Cr sources (Cr chloride and CrPic) and levels on the growth performance and immune responses of broilers vaccinated with AI virus vaccine so as to provide an effective nutritional strategy for improving immune function of broilers. A total of 432 1-day (d)-old male broiler chicks were used in a 1 plus 2×4 design. Chickens were given either a diet without Cr supplementation (control) or diets supplemented with 0.4, 0.8, 1.6, or 3.2 mg Cr/kg as either Cr chloride or CrPic for 42 d. Compared to the control, dietary Cr supplementation had no effect (P>0.05) on average daily gain, average daily feed intake and gain : feed of broilers during the starter and grower phases, but increased (P<0.05) the relative weights of bursa of fabricius on d 21 and thymus, spleen, or bursa of fabricius on d 42, serum antibody titers against AI virus on d 21, 28, 35 and 42, blood T-lymphocyte transformation rate on d 28 and 42, blood T-lymphocyte percentage on d 42, and serum interleukin-2 contents on d 28. Broilers fed the diets supplemented with the inorganic Cr chloride had higher (P<0.05) weights of thymus, spleen and bursa of fabricius than those fed the diets supplemented with the CrPic on d 42. In addition, broilers fed the diets supplemented with the CrPic had higher (P<0.05) antibody titers against AI virus than those fed the diets supplemented with the inorganic Cr chloride on d 21 and 35. These results indicate that dietary Cr supplementation improved immune responses of broilers vaccinated with AI virus, and the inorganic Cr chloride was more effective than the CrPic in increasing the relative weights of lymphoid organs, however, the CrPic was more effective than the inorganic Cr chloride in enhancing the serum antibody titer against AI virus.     

Effect of diet composition on feeding,digestion, and reproduction in Glossina morsitans

Quantitative estimates of food intake by adult female Glossina morsitans were made using ⁴⁵Ca in the diet. Rate of digestion was measured by estimating residual nitrogen in the gut contents at various intervals after feeding. Results show that the superiority of pig blood over cow blood as a diet for in vitro feeding of Glossina cannot be explained in terms of quantities ingested or in terms of digestion rate by the fly. Comparing blood from a number of mammalian hosts, only that of pig elicited production of optimal sized offspring and no correlation could be found between haemoglobin content or trypsin inhibition capacity and offspring size for any of the bloods tested. An exchange of protein fractions between pig and cow blood failed to demonstrate a specific component of pig blood which accounts for its nutritional superiority. Removal of serum, and suspension of washed pig erythrocytes in a saline solution resulted in production of very small offspring. However, the addition of physiological concentrations of soluble albumen to such a suspension produced an improvement in both fecundity and offspring size. Feeding on serum alone or upon serum containing added albumen in solution resulted in poor survival and fecundity was reduced to zero. Results emphasize the importance of both serum and erythrocyte components of blood in providing an optimal diet for Glossina.     

The passage of orally fed proteins from mother to foetus in the rat

Pregnant rats were orally fed with a mixture of bovine IgG, bovine albumin, ovalbumin and beta-lactoglobulin. Using immunoprecipitation methods, these proteins were detected in the maternal blood serum, urine and uterine fluids, and also in the foetal blood serum and the amniotic fluid. The results imply that a variety of dietary proteins, still immunoprecipitable, are able to cross the materno-foetal barriers to be detected in the foetal circulation, where they may influence the maturation of the immune system of the foetus.     

Effects of variations in a formulated protein meal on the fecundity and fertility of female mosquitoes

Abstract. A formulated protein meal developed by Kogan (1990) for adult female Aedes aegypti mosquitoes was evaluated and modified to increase egg and pupal yield. A vigorous laboratory colony was maintained with the females fed exclusively on this dietary formula for about twenty-five generations over more than 2 years. Extra modifications were made to produce a diet suitable for Anopheles arabiensis and Anopheles stephensi females to produce eggs. Both formulations contain bovine albumin, haemoglobin and globulin in a ringer based solution, plus ATP as a phagostimulant for Ae.aegypti. Compared to Kogan's original, our Aedes formula doubled the production of pupae per female after a single meal, although the yield was still significantly lower than from mosquitoes fed on animal hosts or defibrinated pig blood. In varying the proportions of different constituents during attempts to optimize the formula, no relationship was found between total protein content (within the range 80–220 mg/ml) and fecundity, percentage hatch or pupal yield of Ae.aegypti. Equivocal results were found when an isoleucine supplement was added to the formula.     

Dietary carbohydrate dictates development of Type 2 diabetes in the Nile rat

Amount and type of dietary carbohydrate (CHO), as well as the CHO:fat ratio, are thought to be critical for both the rate of development and severity of Type 2 diabetes mellitus. Thus, these nutritional considerations were examined in the previously described “spontaneous” model of diabetes and metabolic syndrome, the Nile rat. Weanling male Nile rats (n=92) were fed semipurified diets, modifying glycemic index and load by changing the amount of fiber or altering the CHO:fat ratio. Random and fasting blood glucose and body weight were assessed, and diabetes was characterized in terms of blood glucose, relevant plasma and liver parameters, food and water intake and terminal organ weights. Nile rats fed with hiCHO became more hyperglycemic than rats fed with modCHO (P<.05), while loCHO and hiCHO+hiFiber rats remained essentially normoglycemic. Liver lipid and glycogen accumulation was associated with severe hyperlipemia in diabetic rats, analogous to metabolic syndrome in humans. Advanced diabetes was linked to liver and kidney damage and elevated blood urea nitrogen with weight loss. Dispersing dietary CHO by fiber or replacing it by moderate fat (reducing the glycemic index and load) delayed the onset of diabetes but did not prevent signs of insulin resistance. A very low content of dietary CHO (high fat) seemed to prevent even these early indicators of insulin resistance. Thus, the Nile rat represents a novel CHO-sensitive model for study of Type 2 diabetes that reliably follows the course of disease in humans.     

Combined or Individual Effects of Dietary Probiotic <Emphasis Type="Italic">Pedicoccus acidilactici</Emphasis> and Nucleotide on Growth Performance,Intestinal Microbiota,Hemato-biochemical Parameters,and Innate Immune Response in Goldfish (<Emphasis Type="Italic">Carassius auratus</Emphasis>)

This study investigated the effect of dietary supplementation of probiotic Pedicoccus acidilactici and nucleotide (separately or combined) on growth performance, intestinal microbiota, hemato-immunological parameters, and immunity response in goldfish (Carassius auratus). Fish (average weight 5–6 g) were acclimatized and divided into eight experimental diets supplemented with P. acidilactici of different concentrations (0.1, 0.2, and 0.3% diet) and nucleotides (0 and 0.5% diet) for 6 months. Fish fed with experimental diets showed significant differences in terms of final weight, weight gain, feed conversion ratio, daily growth rate, and condition factor when compared to control diet (P < 0.05). Fish fed with probiotic (0.3%) separately and combined with nucleotide (0.5%) had highest RBC and WBC when compared to other diets (P < 0.05), while the highest values for Hb and Hct as well as total protein, glucose, albumin, and globulin were observed in probiotic (0.2%) and nucleotide (0.5%) combined diet. Serum lysozyme and anti-protease activities were significantly higher in probiotic (0.1 and 0.2%) and nucleotide (0.5%) combined diets. Similarly, these two diets combined showed the highest colonization of P. acidilactici when compared to other diets. In conclusion, combined dietary probiotic and nucleotide improve the growth performance, hemato-biochemical parameters, and intestine growth in C. auratus.     

Dietary essential oils improve feed efficiency and hepatic antioxidant content of broiler chickens

The aim of this study was to test the hypothesis of an improved growth, dietary nutrient availability and overall health of broiler chickens reared on recycled litter when fed a standardised combination of essential oils (EO; carvacrol, cinnamaldehyde and capsicum oleoresin). To assess the effect of dietary treatments, feed intake, weight gain, feed efficiency, availability of dietary nutrients and energy, villus morphometry, excreta sialic acid concentration, hepatic antioxidants and serum amyloid A (SAA) when fed to broiler chickens were evaluated. Counts of Eimeria spp. oocysts were also determined in excreta samples. Four experimental diets were offered, including two basal control diets based on either wheat or maize that contained 215 g CP/kg and 12.13 MJ/kg metabolisable energy and another two diets using the basal control diets supplemented with the EO combination at 100 mg/kg diet. Each diet was fed to eight floor pens, containing two birds each, following randomisation. Birds fed the EO-supplemented diets had an improved (P<0.05) feed conversion ratio (FCR). Birds fed maize-based diet had an improved daily weight gain and FCR (P<0.05) compared with wheat-fed birds. Wheat-based diet tended (P=0.056) to have greater N-corrected apparent metabolisable energy and had greater fat retention coefficient (P<0.05) compared with maize-based diets. No differences (P>0.05) were observed in villus morphometry, sialic acid secretion, number of oocysts and SAA. Feeding the EO improved (P<0.05) the retention of dietary Ca and Na. Compared with maize, feeding wheat-based diets improved the retention coefficients for Ca, P and Na (P<0.05). Feeding dietary EO improved (P<0.05) the concentrations of the hepatic antioxidants, including carotene, coenzyme Q₁₀ and total vitamin E. The hepatic concentration of carotene of the maize-fed birds was 55.6% greater (P<0.05) compared with the wheat-fed birds. These results demonstrated that the addition of a standardised combination of EO in wheat- and maize-based diets provided benefits in terms of feed efficiency, mineral retention and antioxidant status of the birds when reared on recycled litter.     

Influence of serum albumin on fecundity and weight of the progeny of the tsetse fly Glossina palpalis palpalis

Females of a membrane-fed colony of G. p. palpalis (food source: fresh defibrinated bovine blood) were fed on derivatives of bovine blood, in which the red cell fraction remained unchanged while the serum fraction was replaced by an artificial solution. This solution consisted of a simple saline, isotonic to serum and enriched by bovine serum albumin with increasing concentrations. Physical parameters such as pH and osmolarity of all media were similar to controls. The absence of serum albumin in the food medium resulted in sterility of the females and caused high mortality. The presence of increased levels of serum albumin in the medium increased the fecundity until it was similar to that of flies fed on the standard diet of fresh defibrinated bovine blood. The offspring size was positively correlated with the concentration of the serum albumin in the mother's diet. However, a high concentration of albumin (>6%) resulted in increased adult mortality. Thus, the presence of optimum amounts of free serum albumin in bovine blood appears necessary for the development and production of viable larvae of the tsetse fly G. p. palpalis.

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Résumé Les femelles d'une population de G. p. palpalis élevées sur membrane (aliment: sang frais défibriné de bovin) ont été nourries de dérivés de sang bovin dont les globules rouges n'avaient pas été modifiés, mais dont le sérum avait été remplacé par une solution artificielle. Cette solution était simple, saline, isotonique au sérum et enrichie d'albumine de sérum bovin en concentrations croissantes. Les témoins ont montré l'identité des paramètres physiques, tels que le pH et l'osmolarité, pour toutes les solutions. L'absence d'albumine de sérum dans l'aliment donné aux femelles a provoqué leur stérilité et une mortalité élevée. L'augmentation des quantités d'albumine de sérum a accru la fécondité jusqu'à ce que celle-ci soit identique à celle des glossines avec un régime normal composé de sang frais défibriné de bovin. Il y avait une corrélation directe entre la taille des descendants et la concentration d'albumine de sérum dans l'alimentation de la mère. Toutefois, une forte concentration d'albumine (plus de 6%) a augmenté la mortalité imaginale. La présence de quantités optimales d'albumine de sérum libre dans le sang bovin semble donc nécessaire au développement et à la production de larves viables de la mouche tsé-tsé, G. p. palpalis.

     

Effects of dietary cholesterol on antioxidant capacity,non-specific immune response,and resistance to Aeromonas hydrophila in rainbow trout (Oncorhynchus mykiss) fed soybean meal-based diets

This study evaluated the effects of dietary cholesterol on antioxidant capacity, non-specific immune response and resistance to Aeromonas hydrophila in rainbow trout (Oncorhynchus mykiss) fed soybean meal-based diets. Fish were fed diets supplemented with graded cholesterol levels (0 [control], 0.3, 0.6, 0.9, 1.2, and 1.5%) for nine weeks. The fish were then challenged by A. hydrophila and their survival rate recorded for the next week. Dietary cholesterol supplementation generally increased the serum and hepatic superoxide dismutase (SOD), glutathione-peroxidase (GSH-Px), catalase (CAT), and total antioxidant capacity (TAC) activities, but decreased the serum and hepatic malondialdehyde (MDA) contents. Further, the hepatic CAT and serum SOD, CAT, and TAC activities were significantly higher in fish fed diets supplemented with 0.9 or 1.2% cholesterol compared to those fed the control diet, whereas the serum and hepatic MDA contents were significantly lower. The respiratory burst activity, alternative complement activity, and hepatic lysozyme activity increased steadily when the supplemental cholesterol was increased by up to 1.2% and then declined with further addition. The serum lysozyme activity and phagocytic activity increased steadily with increasing dietary supplemental cholesterol level up to 0.9% and then declined with further addition. Dietary cholesterol supplementation generally enhanced the protection against A. hydrophila infection, and fish fed diets supplemented with 0.9 or 1.2% cholesterol exhibited the highest post-challenge survival rate. The results indicated that cholesterol may be under-supplied in rainbow trout fed soybean meal-based diets, and dietary cholesterol supplementation (0.9–1.2%) contributed to improved immune response and disease resistance of rainbow trout against A. hydrophila.     

Studies on the biochemical basis of the nutritional quality of tsetse fly diets

Batches of freeze-dried pig and cow blood, whose nutritional value to G. p. palpalis ranged from low to near optimum, were analysed for amino acid, triglyceride and cholesterol content. The results of the chemical analyses were compared with the nutritional quality parameters observed when each batch of blood was fed to G. p. palpalis in an attempt to establish a chemical basis for the nutritional quality of diets for Glossina. In general, those pig or cow blood diets that had a higher nutritional quality also had a significantly higher amino acid content than the suboptimal diets. There were significant differences between the triglyceride and cholesterol content of pig and cow blood, with pig blood having more triglyceride, but less cholesterol than bovine blood. There was no apparent correlation between the triglyceride and cholesterol content and the nutritional quality of blood.     

Response of rumen microbiota,and metabolic profiles of rumen fluid,liver and serum of goats to high-grain diets

Feeding ruminants a high-grain (HG) diet is a widely used strategy to improve milk yield and cost efficiency. However, it may cause certain metabolic disorders. At present, information about the effects of HG diets on the systemic metabolic profile of goats and the correlation of such diets with rumen bacteria is limited. In the present study, goats were randomly divided into two groups: one was fed the hay diet (hay; n = 5), while the other was fed HG diets (HG; n = 5). On day 50, samples of rumen contents, peripheral blood serum and liver tissues were collected to determine the metabolic profiles in the rumen fluid, liver and serum and the microbial composition in rumen. The results revealed that HG diets reduced (P < 0.05) the community richness and diversity of rumen microbiota, with an increase in the Chao 1 and Shannon index and a decrease in the Simpson index. HG diets also altered the composition of rumen microbiota, with 30 genera affected (P < 0.05). Data on the metabolome showed that the metabolites in the rumen fluid, liver and serum were affected (variable importance projection > 1, P <0.05) by dietary treatment, with 47, 10 and 27 metabolites identified as differentially metabolites. Pathway analysis showed that the common metabolites in the shared key pathway (aminoacyl-transfer RNA biosynthesis) in the rumen fluid, liver and serum were glycine, lysine and valine. These findings suggested that HG diets changed the composition of the rumen microbiota and metabolites in the rumen fluid, liver and serum, mainly involved in amino acid metabolism. Our findings provide new insights into the understanding of diet-related systemic metabolism and the effects of HG diets on the overall health of goats.     

Effects of dietary chromium picolinate and peppermint essential oil on growth performance and blood biochemical parameters of broiler chicks reared under heat stress conditions

A study was conducted using 240 female day-old broiler chicks to evaluate the effects of dietary chromium picolinate (CrPic), peppermint essential oil (P.mint), or their combination on growth performance and blood biochemical parameters of female broiler chicks raised under heat stress conditions (HS, 23.9 to 38 °C cycling). Average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were obtained from 1 to 42 days of age. Furthermore, at the end of the experiment (day 42), birds were bled to determine some blood biochemical parameters and weighed for final body weight (BW). ADFI, ADG, and BW were not influenced significantly by dietary CrPic and P.mint (P?>?0.05). A significant interaction between dietary CrPic and P.mint on FCR (P?=?0.012) was detected. FCR significantly decreased in chicks fed the diet including both CrPic and P.mint compared with the CrPic group. Significant interaction between dietary P.mint and CrPic on serum concentrations of triglycerides, glucose, and albumin were observed (P?<?0.05), but the other measured blood biochemical parameters were not statistically affected by dietary treatments (P?>?0.05). The serum concentrations of glucose, triglycerides were decreased (P?<?0.05) in broilers fed the diet including both CrPic and P.mint. Plasma chromium (Cr) content increased significantly (P?<?0.05) in birds fed the CrPic-included diet compared with the control group (P?<?0.05). From the results of the present experiment it can be concluded that dietary supplementation with combined P.mint and CrPic could have beneficial effects on some blood biochemical parameters of female chicks reared under heat stress conditions.