Efficacy of dietary supplemental insoluble fibrous materials in ameliorating adverse effects of coccidial challenge in broiler chickens

ABSTRACT

The current experiment was designed to examine effects of dietary supplemental sunflower hulls (SH) and rice hulls (RH) on growth performance, carcass traits, intestinal morphology, lesion score and oocyst shedding in broiler chickens exposed to coccidial challenge. A total of 540 broiler chickens (Ross 308) were assigned to six dietary treatments based on a factorial arrangement (2 × 3) across 1–14, 14–28 and 28-42-d periods. Experimental treatments consisted of broiler chickens without or with coccidial challenge each offered with three different diets: a basal diet or basal diet supplemented with either RH or SH at 40 g/kg diet, respectively. Infection with Eimeria impaired daily weight gain (DWG) and feed conversion ratio (FCR) of broiler chickens during growing period (p < 0.05) while supplementation of SH or RH reduced the adverse effect of coccidiosis so that birds had similar DWG to those fed the basal diet without infection. However, only dietary SH improved the FCR of broilers challenged with coccidiosis. Regardless of coccidial challenge, dietary access to insoluble fibre improved performance of broilers across the growing period (p < 0.05); however, this effect was not observed during the entire rearing period. Relative weights of liver and pancreas were increased in birds subjected to coccidial challenge on d 21 of age (p < 0.05). Moreover, relative weights of the intestinal segments were enhanced (p < 0.05). Furthermore, gizzard weights were higher in birds receiving diets added with fibre (p < 0.05). Infection with coccidiosis decreased villus height and villus height to crypt depth ratio in duodenum of broilers which received the basal diet compared with those fed the same feed without coccidial challenge (p < 0.05). However, supplemental SH could decrease the negative effect of infection on the noted intestinal morphometric attributes. Similarly, a marked reduction was observed for lesion score and faecal oocyst excretion of challenged broilers fed on dietary supplemental fibre (p < 0.05). In conclusion, supplementation of insoluble fibre could ameliorate negative effects of coccidial challenge on DWG of broiler chickens and inclusion of SH in diet of birds exposed to Eimeria infection could be recommended.     

Effects of feeding intact,ground and/or pelleted rapeseed on nutrient digestibility and growth performance of broiler chickens

ABSTRACT

In this study, the effect of grinding or pelleting of rapeseed on the digestibility, apparent metabolisable energy (AME_N), growth performance and gizzard weight of broiler chickens was evaluated. In Exp. 1, four treatments were tested (240 broiler chickens, 20 replications, 3 birds per cage). Birds received either a basal diet or were fed with rapeseed of different sized particles (fine, medium and coarse ground, respectively). In Exp. 2, 10 treatments were assessed (360 chickens, 12 replications, 3 birds per cage), where five different diets (a basal diet and four diets with intact rapeseed, fine ground, medium ground or coarse ground rapeseed, respectively) were fed non-pelleted or pelleted. In Exp. 3, two treatments were compared (224 broiler chickens, 14 replications, 8 birds per floor pen): fine ground rapeseed (FG) and intact rapeseed (IS). Compared with medium and coarse ground rapeseed, fine grinding increased in Exp. 1 the AME_N of rapeseed and the precaecal digestibility (PD) of dry matter and ether extract (EE) (p < 0.05). In Exp. 2, the content of AME_N and the PD of EE and crude protein (CP) increased as the degree of grinding increased when diets were not pelleted (p < 0.01). In contrast, the significantly highest values for these parameters were measured after pelleting without effect of grinding, resulting in a significant interaction between pelleting and grinding (p < 0.001). In Exp. 3, performance of chickens was not affected by dietary treatments, but gizzard weight and the PD of CP were higher when IS were included in the diet (p < 0.05). The results suggested that fine grinding may be used to increase the feeding value of full-fat rapeseed for broiler chickens. Nevertheless, pelleting of diets with rapeseed seemed to be much more effective in the reduction of particle size than grinding.     

Supplemental zinc and vitamin A can alleviate negative effects of heat stress in broiler chickens

This experiment was conducted to evaluate the effects of zinc (ZnSO₄H₂O) and vitamin A (retinol) supplementation on performance, carcass characteristics, and serum concentrations of glucose, cholesterol, total protein, and malondialdehyde (MDA) as an indicator of lipid peroxidation in broiler chickens (Ross) reared at a high temperature (34°C). One hundred twenty 10-d-old male broilers were randomly assigned to 4 treatment groups, 3 replicates of 10 birds each. The birds were fed either a basal diet or the basal diet supplemented with either 30 mg Zn/kg diet, 4.5 mg (15,000 IU) retinol/kg diet, or 30 mg Zn+4.5 mg retinol/kg diet. Supplemental zinc and vitamin A significantly increased live weight gain and improved feed efficiency (p<0.05). However, a combination of zinc and vitamin A, rather than each separately, provided a greater performance. Hot and chilled carcass weights and yields and the weights of internal organs with the exception of abdominal fat were greater for each supplement (p<0.05) compared to the control group. Abdominal fat decreased (p<0.05) upon dietary zinc and vitamin A supplementation. Supplemental treatments resulted in an increased total serum protein but decreased glucose, cholesterol, and MDA concentrations. The results of the study show that, separtely or as a combination, zinc and vitamin A supplementation resulted in an improved live weight gain, feed efficiency, and carcass traits, as well as a decrease in serum MDA concentrations. The results of the present study also suggest that zinc and vitamin A have similar effects and that a combination of zinc and vitamin A may offer a potential protective management practice in preventing heat-stress-related depression in performance of broiler chickens.     

Melatonin supplementation can ameliorate the detrimental effects of heat stress on performance and carcass traits of Japanese quail

Melatonin, the major pineal hormone, modulates growth in poultry by influencing hormones involved in growth. We investigated the effects of dietary melatonin supplementation on performance, carcass characteristics, and excretion of nitrogen and some minerals in broiler Japanese quails (Coturnix coturnix japonica) exposed to high-ambient-temperature stress (34°C). One hundred twenty Japanese quails (10 d old) were randomly assigned to 4 treatment groups, 3 replicates of 10 birds each. The birds were kept in either an environment-controlled room at a constant 22°C or were kept at 22°C for 16 h/d and at 34°C for 8 h/d (9:00 am to 5:00 pm). At both temperatures birds were fed either a basal diet or the basal diet supplemented with 40 mg of melatonin per kilogram of diet. The experiment lasted for 32 d. Melatonin improved feed efficiency in both temperatures groups compared with their corresponding controls. Although feed intake was similar in all groups, the improvement in feed efficiency was more noticable in melatonin-fed quails kept at high temperature (p<0.01). Supplemental melatonin significantly increased live weight gain and carcass characteristics under stress conditions (p<0.01) but did not show the same effect at thermoneutral conditions (p>0.05). Heat exposure increased excretion of N, Ca, P, Zn, Fe, and Cr and decreased retention rates for them. Dietary melatonin supplementation returned these values to normal (p<0.01). No interactions between melatonin and temperature were found in the parameters measured. The results of the study show that melatonin supplementation attenuated the retardation in performance as well as the excretion of minerals caused by heat stress in broiler quails. Our data suggest that melatonin might offer protection against heat-stress-related depression in the performance of broiler quails.     

Effects of glyceryl polyethylene glycol ricinoleate on nutrient utilisation and performance of broiler chickens

A completely randomised design study with a 2 × 2 factorial arrangement was conducted to observe effects of an emulsifier (glyceryl polyethylene glycol ricinoleate (GPR)) on nutrient utilisation and performance of broiler chickens. A total of 384 male broiler chickens were used to determine the influence of GPR (without addition or added at 0.04% of diet) and two levels of apparent metabolisable energy (AME_N) (according to standard requirements (Diets SE) or energy reduced by 0.4 MJ/kg diet (Diets LE)) on birds’ performance and apparent total tract digestibility (ATTD). ATTD of ether extract (EE) and AME_N were measured on d 14 and 35, and ATTD of neutral detergent fibre (NDF) was measured on d 35. All diets were based on wheat–maize–soybean meal with rapeseed oil and lard (blend of 50:50) as fat sources. During the grower period and the whole trial, birds fed Diets supplemented with GPR were characterised by higher body weight gain (BWG) and lower feed conversion ratio (FCR) compared to chicken receiving diets without GPR (p < 0.05). At the end of experiment, birds fed Diet LE without GPR were characterised by lower BWG and higher FCR (p < 0.05). Supplementation with GPR caused a higher ATTD of EE for diets SE and LE at d 14 and 35 (p < 0.05). Moreover, the GPR addition to Diet LE improved ATTD of NDF at d 35 (p < 0.05). In conclusion, the findings suggest that GPR effects the digestion of a blend of animal fat/rapeseed oil positively, even in a practical maize–wheat-based broiler diet with decreased AME_N level.     

Early age thermal manipulation on the performance and physiological response of broiler chickens under hot humid tropical climate

Initial brooding temperature is critical for post-hatch growth of broiler chickens. A study was conducted to investigate the early age thermal manipulation (EATM) on the performance and physiological responses broiler chickens under hot humid tropical climate. A total of 260 unsexed day-old Arbor-acre broiler chicks were assigned to five thermal treatments of brooding temperature regimens having 4 replicates of thirteen birds each. The heat treatments were: initial brooding temperature of 35 °C for the first 2 days, and then decreased subsequently, gradually to 22 °C at 21 d of age (CT), initial temperature of 35 °C, sustained for the first 4 days and then decreased gradually (conventionally) (FD), initial temperature of 35 °C for the first 7 days (SD), the birds in CT, but the brooding temperature was raised to 35 °C again for another 3 days from day 7 (SD3), initial brooding temperature of 35 °C for the first 10 days (TD). Data were collected on daily feed intake and weekly body weights. Blood samples were collected from 8 birds per treatment weekly for the determination of plasma uric acid, triglycerides, triiodothyronine (T₃) and creatinine kinase. Data obtained were laid out in a Completely Randomized Design (CRD). Results showed that the final weights of the birds in FD were higher (P < 0.05) than those of the other treatments at the finisher phase. Feed intake of the birds in FD was higher than those of SD3 and TD. FCR of broiler chickens in CT, SD, SD3 and TD was higher than that of FD. The rectal temperature, plasma MDA and blood glucose of the thermally challenged birds in FD was generally better (P < 0.05) than those of the other treatments. It was concluded that EATM can be used to improve performance and also protect broiler chickens from acute heat stress at market age.     

Eucalyptus leaves powder,antibiotic and probiotic addition to broiler diets: effect on growth performance,immune response,blood components and carcass traits

The study was conducted to investigate the effects of different levels of eucalyptus powder (EP), virginiamycin and probiotic on performance, immunity, blood components and carcass traits of broiler chickens. A total of 250, 1-day-old male broiler chickens (Ross 308) were randomly allocated to five treatments with five replicates and 10 chicks each, as a completely randomized design. The dietary treatments consisted of: basal diet (BD), BD+0.25% EP, BD+0.5% EP, BD+0.01% of diet probiotic (Protexin), BD+0.02% of diet antibiotic (virginiamycin). Dietary supplementation did not affect feed intake, BW gain (BWG) and feed conversion ratio (FCR) during starter and grower phases, but BWG and FCR were affected during the finisher and whole periods (P<0.05).The highest BWG and lowest FCR were obtained in birds fed with virginiamycin and 0.5% EP. Dietary supplementation significantly increased the relative weight of carcass and breast (P<0.05). Treatments had no effect on relative weights of internal organs and small intestine except for bursa that increased by treatments. Relative length of jejunum also increased by treatments (P<0.05). Antibody production against sheep red blood cells did not changed in primary titer (day 35), but it significantly increased in secondary titer (day 42) by 0.5% EP. White blood cell counts were increased and cholesterol decreased by dietary supplementation (P<0.05). In conclusion, the results of this study showed that 0.5% EP served as a useful replacement for antibiotic and would improve performance and immune response of broiler chickens.     

Effects of source and level of magnesium on catalase activity and its gene expression in livers of broiler chickens

Abstract

The effects of dietary supplemental magnesium oxide (MgO), magnesium-L-aspartate (MgAsp) and monomagnesium-di-L-aspartate (MgdiAsp) on hepatic catalase (CAT) activity and its mRNA expression were investigated. A total of 360 one-day-old male Abor Acre broiler chickens were allocated to ten treatments, i.e. control plus 9 treatments from 3×3 factorial arrangement (Mg source, Mg level), each treatment with six replicates of 6 chickens. The birds were fed with the basal diet alone or supplemented with magnesium (Mg) at 0.9, 1.8, 2.7 g/kg of the diet from MgO, MgAsp or MgdiAsp. Results showed that hepatic Mg concentration increased quadratically as MgO or MgAsp supplementation increased (p < 0.01). Hepatic CAT activity increased linearly in birds fed with MgAsp or MgdiAsp (p < 0.01) and quadratically in birds fed with MgO (p < 0.05) as dietary Mg supplementation level increased. Hepatic CAT mRNA was linearly correlated with the dietary Mg supplementation level (p < 0.01). There were positive correlations among hepatic CAT activity, its mRNA expression level and hepatic Mg concentration (p < 0.01). No effect of Mg²⁺ on the purified CAT activity was detected in vitro enzymatic reaction system (p > 0.05). Supplemental MgAsp or MgdiAsp was more efficient to increase hepatic Mg concentrations, enhance hepatic CAT activity and its mRNA expression than MgO (p < 0.01). It can be concluded that dietary Mg supplementation could increase hepatic Mg concentration, enhance CAT mRNA expression and consequently enhance CAT activity, and the organic Mg (MgAsp or MgdiAsp) is much more efficient than the inorganic form (MgO).     

Effects of conjugated linoleic acids on growth performance,serum lysozyme activity,lymphocyte proliferation,and antibody production in broiler chicks

Abstract

This study was conducted to investigate the effect of dietary conjugated linoleic acids (CLA) on growth performance and immune responses in broiler chicks. A total of 240 day-old Arbor Acre male broiler chicks were randomly allotted into four dietary treatments with different inclusion levels of CLA (0, 2.5, 5.0 or 10.0 g/kg) for six weeks. Growth performance, peripheral blood lymphocyte (PBL) proliferation, lysozyme activity, phagocytic activity (carbon clearance) and serum antibody titers against Newcastle disease virus (NDV) vaccine were examined. There were no significant differences in growth performance among treatments (p > 0.05). Chicks fed CLA diets produced more lysozyme activity in serum than the control group at 2 and 6 weeks of age (p < 0.05). Dietary CLA enhanced the PBL proliferation in response to concanavalin A (ConA) at the age of 42 d (p < 0.05). Phagocytic ability was also affected by dietary CLA and chicks fed CLA diets had faster carbon clearance rate (p < 0.05), but antibody titers to NDV was not influenced by dietary CLA. The results of the study suggested that dietary CLA could enhance innate and cellular immune response in broiler chicks, and not affect the growth performance.     

Effects of betaine and condensed molasses solubles on nitrogen balance and nutrient digestibility in piglets fed diets deficient in methionine and low in compatible osmolytes

Abstract

A balance experiment was carried out to investigate the effects of betaine monohydrate (BET) or betaine derived from condensed molasses solubles (CMS) as a substitute for methionine and choline on nitrogen (N) balance and total tract nutrient digestibility in weaned piglets. The experiment included four treatments with 32 barrows with an average initial body weight (BW) of 13.5 kg. The supplementation of DL-methionine and choline (positive control = PC) to the basal diet, which was deficient in methionine and low in compatible osmolytes in the form of betaine or its precursor choline (negative control = NC) resulted in a significant increase in N retention of 0.8 g/d. The substitution of DL-methionine and choline with BET or CMS did not affect N retention compared to the PC and the NC treatment either. Feeding the PC diet increased the digestibilities of organic matter, NDF, ADF, NFE, crude ash, Ca, P, methionine, tryptophan and cystine by 1.9%, 7.3%, 9.7%, 1.1%, 6.3%, 13.9%, 7.7%, 15.9%, 4.3% and 2.8%, respectively, and tended (p < 0.20) to increase the digestibilities of most other amino acids by 1.6 – 3.4%. Digestibility of CP, EE (HCl), Mg and Na was 3.1% (p = 0.09), 5.1% (p = 0.09), 5.1% (p = 0.06) and 3.3% (p = 0.17) higher, respectively, when compared to the NC treatment. BET and CMS supplementation increased most nutrient digestibilities in the same magnitude as for the PC treatment. In summary, the supplementation of betaine, originating from different sources, to a diet with low contents of compatible osmolytes increased in particular the fermentation of fibre and enhanced mineral absorption. The supplementation of the NC with DL-methionine was more efficient in improving N retention than the replacement of DL-methionine by betaine originating from BET or CMS.     

Cottonseed Meal Bioactive Peptides as an Alternative to Antibiotic Growth Promoters in Broiler Chicks

The aim of this experiment was to evaluate the effects of bioactive peptides derived from enzymatic hydrolysis of cottonseed meal (CSBP) compared with zinc bacitracin, as an antibiotic growth promoter (AGP), on productive traits, serum lipid profile, and ileal microbial population in broiler chickens. A total number of 240-day-old broiler chicks (Ross 308) were allocated into 4 treatments, replicated 5 times based on a completely randomized design. The dietary treatments included a basal diet serving as control group, basal diet?+?40 mg/kg zinc bacitracin as AGP group, and the basal diet supplemented with 15 or 20 g/kg CSBP substituting equal quantity of maize and soybean meal. Performance traits, including daily weight gain, feed intake, feed conversion ratio (FCR), and livability were recorded. At the end of the study, serum lipid parameters, ileal microbial population, and economical indices were determined. The results indicated that feed intake and FCR increased (P?<?0.05) in birds receiving 20 g/kg CSBP over the entire period (1–35 days), but there was no significant effect of CSBP on body weight, although numerically higher than the control group. However, the antibiotic group showed a significant increase (P?<?0.05) in body weight and feed intake. Livability, European Production Efficiency Factor (EPEF), and European Broiler Index (EBI) significantly improved in broiler chickens fed antibiotic and 15 g/kg CSBP supplement (P?<?0.05). Adding 20 g/kg of CSBP to the diet significantly increased serum triglycerides and decreased low-density lipoproteins (LDL) compared to the control and antibiotic groups on day 35. The relative weight of abdominal fat and LDL to HDL ratio were significantly lower for CSBP and antibiotic treatments than the control group (P?<?0.05). Supplementation of antibiotic and both graded levels of CSBP decreased the ileum population of Escherichia coli (P?<?0.05). The current findings suggest that including CSBP in broiler diets may benefit production through improving growth rate of broilers and balancing gut microbiota population. In addition, CSBP could be considered as a potential alternative to antibiotics in an AGP free production system.

     

Metabolism and Tissue Distribution of Trace Elements in Broiler Chickens' Fed Diets Containing Deficient and Plethoric Levels of Copper,Manganese, and Zinc

Supplementation of broiler diets with copper, manganese, and zinc at levels higher than that stipulated by the National Research Council 1994 reportedly improved live weight, feed conversion, and cured leg abnormality supposedly caused by inadequate intake of Mn and Zn. The objective of the study was to ascertain the effects of plethoric supplementation of copper (Cu), manganese (Mn), and zinc (Zn) on performance and metabolic responses in broiler chickens. The study also aimed to discriminate the responses of the birds when the mineral elements were supplemented either in an inorganic or in an organic form. Cobb 400 broiler chickens (1-day old, n = 300) were assigned to three dietary treatments each containing nine replicates with ten birds for 39 days. The treatments included a control in which the diet was devoid of supplemental trace elements and treatments supplemented with an inorganic trace element premix (ITM) and supplemented with a combination of the inorganic and an organic trace element premix (OTM). The ITM contained (per kilogram) copper, 15 g; iron, 90 g; manganese, 90 g; zinc, 80 g (all as sulfated salts); iodine (as potassium iodide), 2 g; and selenium (as sodium selenite), 0.3 g. The OTM on the other hand, contained copper, 2.5 g; iron, 15 g; manganese, 15 g; zinc, 13.33 g; and chromium, 0.226 g (all as protein chelates). Plethoric supplementation of trace elements improved live weight gain and feed/gain ratio (p < 0.05). Leg abnormality developed in the 16% of the control group of birds but not in the supplemented group. Metabolizability of dry matter, organic matter, and protein was higher (p < 0.01) in the ITM and OTM groups. Excretion of Cu, Fe, and Zn decreased (p < 0.1) due to supplementation of the trace elements leading to increased apparent absorption of the said mineral elements (p < 0.01). Concentration of the concerned trace elements in serum, liver, and composite muscle samples was higher (p < 0.05) in the ITM and OTM dietary groups indicating an increased deposition of the said mineral elements due to supplementation. Although the study revealed subtle difference between the inorganic and organic mineral premixes with regards to the parameters mentioned above, it became apparent that it is possible to reduce excretion of these trace elements by a judicious escalation in the level of supplementation. The results of the present investigation further revealed that the trace mineral requirement of broiler chickens suggested by the National Research Council may not be optimum to support the maximum growth potential of the high yielding strains, and it is reasonable to consider a review of the current NRC recommendations to meet the needs of the modern birds.     

Effects of dietary pyrroloquinoline quinone disodium on growth performance,carcass yield and antioxidant status of broiler chicks

Pyrroloquinoline quinone (PQQ), a putative essential nutrient and redox modulator in microorganisms, cell and animal models, has been recognized as a growth promoter in rodents. Growth performance, carcass yield and antioxidant status were evaluated on broiler chickens fed different levels of PQQ disodium (PQQ.Na₂). A total of 784 day-old male Arbor Acres (AA) broilers were randomly allotted into seven dietary groups: negative control group (NC) fed a basal diet without virginiamycin (VIR) or PQQ.Na₂; a positive control group (PC) fed a diet with 15 mg of VIR/kg diet; and PQQ.Na₂ groups fed with 0.05, 0.10, 0.20, 0.40 or 0.80 mg PQQ.Na₂/kg diet. Each treatment contained eight replicates with 14 birds each. The feeding trial lasted for 6 weeks. The results showed that chicks fed 0.2 mg PQQ.Na₂/kg diet significantly improved growth performance comparable to those in PC group, and the feed efficiency enhancement effects of dietary PQQ.Na₂ was more apparent in grower phase. Dietary addition of PQQ.Na₂ had the potential to stimulate immune organs development, and low level dietary addition (<0.1 mg/kg) increased plasma lysozyme level. Broilers fed 0.2 mg PQQ.Na₂/kg diet gained more carcasses at day 42, and had lower lipid peroxide malondialdehyde content and higher total antioxidant power in plasma. The results indicated that dietary PQQ.Na₂ (0.2 mg/kg diet) had the potential to act as a growth promoter comparable to antibiotic in broiler chicks.     

The effect of Boswellia serrata resin diet supplementation on production,hematological, biochemical and immunological parameters in broiler chickens

Boswellia serrata resin (BSR), exhibiting a variety of therapeutic properties, is applied in Asian traditional medicine. These properties can be used in poultry production as well. Application of the resin as a phytobiotic in broiler chicken rearing can increase the productivity and improve meat quality. However, the optimum and maximum levels of BSR in broiler diets need to be assessed. The study determined the effect of different levels of supplementation of BSR (directly derived, unprocessed) in diets for broiler chickens on the production traits, selected slaughter analysis parameters, nutrient digestibility and selected hematological, biochemical and immunological parameters. In total, 200 1-day-old broiler chickens were assigned randomly to four treatments with five replicate cages of 10 broiler chickens/cage (five females and five males). The experiment lasted 6 weeks, and the broiler chickens were fed diets containing 0% (control), 3% (BSR3), 4% (BSR4) or 5% (BSR5). In the broiler chickens receiving diets with addition of resin BSR3 and BSR4, there was an increase in (P<0.05) BW gain, ether extract, ADF, organic matter and energy digestibility of the diets. Moreover, the best carcass quality with a high proportion of muscles and low abdominal fat content (P<0.05) was noted in these groups. The content of uric acid (P<0.01) and the activity of aspartate aminotransferase (P<0.001) and alkaline phosphatase (P<0.05) in blood plasma decreased upon the BSR supplementation. Globulin content increased in blood plasma (P<0.05) along the increasing level of BSR. The blood immunoglobulin A concentration was only affected by the BSR treatments (P<0.05). It may be concluded that BSR can be regarded as a safe and effective dietary additive for broiler chicken.     

Cloacal temperature responses of broiler chickens administered with betaine and ascorbic acid during the hot-dry season

The experiment was performed to evaluate cloacal temperature (CT) responses in broiler chickens, administered with betaine and ascorbic acid (AA) during the hot–dry season. Broilers were divided into four groups: Group I (control) was given sterile water; Group II, betaine at 250 mg/kg; Group III, AA at 50 mg/kg and Group IV, betaine (250 mg/kg) + AA (50 mg/kg). The different solutions were given orally for 42 days. Dry-bulb temperature (DBT), relative humidity (RH) and temperature-humidity index (THI) in the pen, and CT of each broiler chicken were measured bihourly (06:00–18:00 h) on days 28, 35 and 42. DBT, RH and THI values were outside the thermo-neutral zone for broiler chickens. Results showed that AA lowered (p < 0.001) CT, while betaine + AA increased (p < 0.001) CT, compared with controls. In conclusion, betaine + AA or AA alone modulated CT responses of broiler chickens subjected to the thermal stress in the hot–dry season.     

Evaluation of efficacy of impregnated curtains in experimental hen houses as a phlebotomine control tool in northeast Argentina

The aim of this study was to evaluate the effectiveness of insecticide‐impregnated curtains against the entry of phlebotomine (Diptera: Psychodidae) flies into experimental slatted hen houses in an area endemic for American cutaneous leishmaniasis (ACL). Three treatments in experimental dwellings containing three chickens each were applied using, respectively, an impregnated curtain (IC), a non‐impregnated curtain (NIC) and no curtain (NC). A control site without chickens (WC) was included. The study used permethrin at 0.05 g/m². During each month for 1 year, each experimental hen house randomly received all treatments. Phlebotomine sandflies were captured using REDILA BL traps placed inside the hen house. Significant differences in abundances of phlebotomine flies/trap/night were observed between treatments (χ² = 17853.58, d.f. = 3, P < 0.0001): 59.7% of phlebotomines were captured in the NC treatment, 26.3% in the NIC treatment, 8.0% in the IC treatment and 6.1% in the WC condition. Nyssomyia whitmani (Antunes & Coutinho) was the most abundant species in all collections (89.9%). These results showed a lower abundance of phlebotomines in the experimental hen house in the IC condition than in the hen house in the NC condition (P < 0.05) and that the presence of NIC represents an effective physical barrier against phlebotomines (P < 0.05). Therefore, the use of curtains may be an alternative eco‐friendly method for the prevention of indoor ACL transmission in slatted dwellings, which represent a common house type in northeast Argentina.     

Influence of Dietary Selenomethionine Supplementation on Performance and Selenium Status of Broiler Breeders and Their Subsequent Progeny

The study was conducted to investigate the effects of dietary maternal selenomethionine or sodium selenite supplementation on performance and selenium status of broiler breeders and their next generation. Two hundred and forty 39-week-old Lingnan yellow broiler breeders were allocated randomly into two treatments, each of which included three replicates of 40 birds. Pretreatment period was 2 weeks, and the experiment lasted 8 weeks. The groups were fed the same basal diet supplemented with 0.30 mg selenium/kg of sodium selenite or selenomethionine. After incubation, 180 chicks from the same parental treatment group were randomly divided into three replicates, with 60 birds per replicate. All the offspring were fed the same diet containing 0.04 mg selenium/kg, and the experiment also lasted 8 weeks. Birth rate was greater (p < 0.05) in hens fed with selenomethionine than that in hens fed with sodium selenite. The selenium concentration in serum, liver, kidney, and breast muscle of broiler breeders, selenium deposition in the yolk, and albumen and tissues' (liver, kidney, breast muscle) selenium concentrations of 1-day-old chicks were significantly (p < 0.01) increased by maternal selenomethionine supplementation compared with maternal sodium selenite supplementation. The antioxidant status of 1-day-old chicks was greatly improved by maternal selenomethionine intake in comparison with maternal sodium selenite intake and was evidenced by the increased glutathione peroxidase activity in breast muscle (p < 0.05), superoxide dismutase activity in breast muscle and kidney (p < 0.05), glutathione concentration in kidney (p < 0.01), total antioxidant capability in breast muscle and liver (p < 0.05), and decreased malondialdehyde concentration in liver and pancreas (p < 0.05) of 1-day-old chicks. Feed utilization was better (p < 0.05), and mortality was lower (p < 0.05) in the progeny from hens fed with selenomethionine throughout the 8-week growing period compared with those from hens fed with sodium selenite. In summary, we concluded that maternal selenomethionine supplementation increased birth rate and Se deposition in serum and tissues of broiler breeders as well as in egg yolk and egg albumen more than maternal sodium selenite supplementation. Furthermore, maternal selenomethionine intake was also superior to maternal sodium selenite intake in improving the tissues Se deposition and antioxidant status of 1-day-old chicks and increasing the performance of the progeny during 8 weeks of post-hatch life.     

Effect of fat type and lysophosphatidylcholine addition to broiler diets on performance,apparent digestibility of fatty acids,and apparent metabolizable energy content

A completely randomized design study with a 3 × 2 factorial arrangement was conducted to evaluate the effects of three different fat sources (soybean oil, tallow, and poultry fat) with or without emulsifier supplementation on performance, coefficient of total tract apparent digestibility (CTTAD) of fatty acids, and apparent metabolizable energy (AME) content in broiler chickens. Two hundred and fifty-two one-day-old male Arbor Acres broiler chickens were randomly divided into 6 different treatments: (T1) basal diet containing soybean oil without lysophosphatidylcholine (LPC) supplementation, (T2) basal diet containing soybean oil with LPC supplementation, (T3) basal diet containing tallow without LPC supplementation, (T4) basal diet containing tallow with LPC supplementation, (T5) basal diet containing poultry fat without LPC supplementation, and (T6) basal diet containing poultry fat with LPC supplementation. Body weight gains from broiler chicks fed diets containing tallow were lower (P<0.05) than the body weight gains from chicks that were fed diets containing soybean oil or poultry fat in both the starter and grower periods. Birds fed diets containing tallow had the highest FCR (P<0.05), followed by the birds that were fed diets containing poultry fat, and soybean oil. The CTTAD of C16:0, C18:2, and C18:3n3 was greater (P<0.05) for broilers fed diets containing soybean oil than for those fed diets containing tallow or poultry fat in the starter period. The addition of LPC increased (P<0.05) body weight gain of broiler chickens in the starter period and the AME of the diets in the grower period, and tended to reduce FCR (P=0.072) in the starter period. LPC supplementation increased (P<0.05) the CTTAD of C16:0, C18:1n7 and C18:1n9 in the starter period, and of C18:2, and C18:3n3 in the grower period (P<0.05). There were no significant interactions between fat sources and the addition of LPC. These data indicated that LPC supplementation can improve body weight gain of broiler chickens in the starter period. This effect may be associated with an increase of CTTAD of FA due to LPC activity.     

Effects of inulin and di-d-fructose dianhydride-enriched caramels on intestinal microbiota composition and performance of broiler chickens

In vitro and in vivo experiments were designed to evaluate the effectiveness of laboratory-made di-d-fructose dianhydride (DFA)-enriched caramels. The DFA-enriched caramels were obtained from d-fructose (FC), d-fructose and sucrose (FSC), or d-fructose and β-cyclodextrin (FCDC). In the in vitro experiment, raftilose and all caramels increased (P<0.05) l-lactate concentration and decreased (P<0.05) pH. Total short-chain fatty acid concentration was higher (P<0.05) than controls in tubes containing raftilose, FSC, FCDC and commercial sucrose caramel (CSC). Raftilose, and all caramels tested except FSC and FC (1%), increased (P<0.01) lactobacilli log₁₀ number of copies compared with the non-additive control. FSC, FCDC and CSC increased (P<0.01) the bifidobacteria number of copies as compared with controls. All additives, except FCDC, decreased (P<0.01) Clostridium coccoides/Eubacterium rectale log number of copies. Compared with controls, raftilose, FC and CSC led to lower (P<0.01) Escherichia–Shigella and enterobacteria. For the in vivo experiment, a total of 144 male 1-day-old broiler chickens of the Cobb strain were randomly assigned to one of the three dietary treatments for 21 days. Dietary treatments were control (commercial diet with no additive), inulin (20 g inulin/kg diet) and FC (20 g FC/kg diet). Final BW of birds fed FC diet was higher (P<0.01) than controls or inulin-fed birds, although feed: gain values were not different. Feed intake of chickens fed FC was higher (P<0.01) than that of inulin-fed birds but not statistically different from controls. Crop pH values were lower (P<0.01) in birds fed FC diet as compared with control diet, with inulin-fed chickens showing values not different from control- or FC-fed birds. Lower (P<0.05) lactobacilli number of copies was determined in the crop, ileum and caeca of birds fed the inulin diet compared with the control diet. Inulin supplementation also resulted in lower (P<0.05) C. coccoides/E. rectale, bacteroides and total bacteria in caecal contents. Addition of FC to broiler diets gave place to lower (P<0.05) enterobacteria and Escherichia–Shigella in crop and caecal contents compared with controls. The bacteroides number of copies increased (P<0.05) as compared with controls in the ileum, but decreased (P<0.05) in the caeca of chickens fed the FC diet. Energy, ADF, NDF and non-starch polysaccharides faecal digestibilities were greater (P<0.05) than controls in chickens fed diets containing inulin or FC. Fat digestibility was higher (P<0.05) in FC-fed birds compared with controls or inulin-fed chickens. In conclusion, DFA-enriched caramels tested here, particularly FC, may represent a type of new additives useful in poultry production.     

Effect of different selenium source (sodium selenite and selenium yeast) on broiler chickens

A feeding experiment was carried out to compare the effects of supplementing a poultry meal-based diet with selenium as sodium selenite or selenium yeast on broiler chickens. Three groups with three replicates of broiler chickens (mean weight 710 ± 5.3 g) were given a basal diet either unsupplemented (control) or supplemented with 0.2 mg Se kg⁻¹ as sodium selenite (trial 1) or selenium yeast (trial 2) respectively, for 21 days. There was significant difference (P<0.05) in Feed Conversion Ratio (FCR) of trials 1 and 2 compared with the control. However, there were no significant differences (P>0.05) in FCR between trials 1 and 2. Final weight, survival rate and Daily Gain (DG) were not affected by the dietary Se source. Chickens fed the basal diet showed lower (P<0.05) selenium content in muscle, kidney, liver and pancreas compared to that fed selenium supplements (trials 1 and 2). Furthermore, trial 2 showed the highest value (P<0.05) among these treatments. However, there was no significant difference (P>0.05) in muscle selenium content of chickens between trials 1 and 2. Glutathione peroxidase (GSH-Px) activities in broiler chickens plasma and liver of all selenium treatment groups (trials 1 and 2) were significantly different (P<0.05) from that of the control. The GSH-Px activity in plasma was higher (P<0.05) in trial 2 compared with trial 1 and the control. However, there was no difference (P>0.05) in hepatic glutathione peroxidase between trials 1 and 2 although the average value of GSH-Px activity in trial 2 presented the trend of increase.