Male Chicks Research Articles

Long-Term Effects of Early Low-Phosphorous Nutritional Conditioning on Broiler Chicken Performance, Bone Mineralization, and Gut Health Under Adequate or Phosphorous-Deficient Diets

Phosphorous is essential for many metabolic functions and the constitution of bones. Poultry have limited ability to use phosphorous from diets, which is mainly excreted and causes environmental concern. For this reason, diets are commonly supplemented with inorganic phosphorus and phytases. It has been suggested that chickens can adapt to an early nutrient restriction by increasing its efficiency of utilization, an adaptation that has been defined as nutritional conditioning. The aim of this study was to investigate a strategy of phosphorous nutritional conditioning by feeding low phosphorous diets during the first week of life as a strategy to improve the efficiency of phosphorous utilization later in life. To test this, 600 male broiler chickens were fed either a standard (control group) or a phosphorous-deficient diet (conditioned group) during the first week of life. Later in life, the effect of conditioning was tested using standard or P-deficient diets during the finishing phase (21–43 d). Conditioning did not affect overall performance, despite finding evidence for reduced relative phosphorous excretion between days 19 to 21, increased duodenal gene expression for the phosphorous transporter SLC34A2 at day 30 (−6% and +17%, respectively), and tendencies for improved phosphorous digestibility (+7%) and tibia mineralization (+6%) at the end of the trial. It is concluded that phosphorous nutritional conditioning early in life can increase subsequent dietary phosphorous utilization and bone mineralization in poultry, although it may not be able to counteract severe phosphorous deficiencies. Further research is required to assess the extent to which phosphorous supplementation in post-conditioning diets may be reduced with this strategy without compromising performance.

The Effects of Shrimp Waste Added to Broiler Diets on Growth Performance, Slaughter and Carcass Characteristics, Intestinal Morphology, Bone Traits, and Fatty Acids in the Meat.

Recycling animal waste is crucial for the circular economy, promoting environmental and sustainability. This study aimed to assess the impact of shrimp waste added to broiler diets on growth performance, slaughter and carcass characteristics, intestinal morphology, bone traits, and fatty acids in the meat. In the study, 315 ROSS-308 male broiler chicks were utilised as the animal subjects. The experiment consisted of five groups based on the timing and amount of shrimp (Penaeus vannamei) waste addition to their diet (Control [C], 1% added the first 11 days [1% FED], 1% added during fattening [1% DF], 2% added during the first 11 days [2% FED], 2% added during fattening [2% DF]). The differences in body weight, body weight gain, total feed intake and total feed conversion ratio, carcass parameters, relative internal organ weights, and fatty acids of thigh and breast meat among the groups were found to be statistically insignificant (p > 0.05). The addition of shrimp waste to the diet only significantly affected the VH/CD ratio in the jejunum, with the C group showing a lower ratio (p < 0.05). Adding shrimp waste to the diet only affected the seedor index of the femur among the characteristics of the leg bones, and an interaction between the period and the group was observed for this trait (p < 0.05). According to the results, up to 2% shrimp waste can be added to the diet without adversely affecting broiler performance, carcass quality, villus and bone properties, and fatty acid composition. The use of shrimp waste in feed can benefit the broiler industry and protect to environment.

Supplementation of Coenzyme Ubiquinone (COQ10) in the semen diluent of Balitbangtan’s Superior Native Chicken in Terms of Spermatozoa Cromatin Damage

The development of technology in the field of animal husbandry is growing very rapidly, apart from ruminants from poultry livestock can also be done artificial insemination used for breeding. According to Apriyanti (2017) The success of the mating system can be seen from the success of livestock mating which is influenced by the quality of the semen produced. One of the supplementations used is coenzyme ubiquinone (CoQ10) where CoQ10 is one of the vitamins such as fat-soluble vitamin E which is endogenously present in the inner membrane of mitochondria of mammals and plants (El-Sayed, et al. 2021). This study used an experimental method or field experiment with 4 treatments and 10 replicates on 4 male KUB chickens aged 12 months and the diluent used was egg yolk lactated ringer. The variables observed in this study wes cromatin damage of spermatozoa before freezing and post thawing. The results obtained in this study chromatin damage before freezing obtained the highest average value of 1.18 ± 0.58 with statistical calculations showed significantly different results (P &lt; 0.05). chromatin damage after thawing back obtained the highest result of 2.80 ± 0.89 with statistical test calculations obtained results that were not significantly different (P &lt; 0.01) to the different levels of Coenzyme ubiquinone in diluents with different levels.

Research Note: Proteases effect on soybean meal: enzyme product and area of production differences on standardized ileal amino acids digestibility of broiler chickens

This study evaluated the effects of two protease products added to feeds having two soybean meal (SBM) sources (South and North of Brazil). A total of five hundred and sixty, 21 d male broiler chickens were allocated into 7 dietary treatments: a nitrogen-free diet (NFD) and other six diets prepared with a 40% replacement of the NFD with each SBM source. Two commercial protease products (RONOZYME® ProAct and ProAct 360TM) were added at 15,000 PROT and 30,000 NFP per kg feed, respectively. After 5-day diet adaptation, all birds were euthanized for ileal digesta collection. Results show that the North SBM sample was inherently higher (P < 0.05) in apparent ileal digestibility (AID) of dry matter (DM), nitrogen (N), and the standardized ileal amino acid digestibility (SIAAD) compared to South SBM sample. The DM digestibility and SIAAD of North SBM sample were not different from the un-treated control and protease treatments (P > 0.05, except Val and Ile, which had higher digestibility with ProAct 360). The DM digestibility and SIAAD from South SBM sample were increased (P < 0.05, except Met, Asp and Cys) with both supplemental proteases. Correlation analysis showed that AA digestibility of the two SBM samples were negatively associated with the effect of protease products. These data demonstrated that the SIAAD of SBM was influenced by SBM source with the South SBM sample being lower than that from the North while the protease effects were more evident in the SBM sample from South; responses of ProAct 360 were superior to ProAct. Exogenous proteases can enhance nutritional value of SBM, particularly for those with inherently low amino acid digestibility.

Interactive effect of dietary metabolizable energy levels with amino acid density in male broiler chickens: carcass yield, nutrient intake, digestibility and excretion

This study aimed to assess the interactive effects of ME and digestible amino acid (AA) densities on carcass yield, breast meat quality, nutrient digestibility, and excretion in male broiler chickens. Twelve experimental diets arranged as a 4 × 3 factorial array with 4 levels of ME (standard, -50, -100, -150 kcal) and 3 digestible AA (standard, +3.0 and +6.0%) were offered to 2400 day-old male Ross 308 broiler chickens. Diets were replicated 8 times with 25 birds per replicate, and fed for starter (0-10 d), grower (11-24 d), finisher (25-35 d), and withdrawal (36-42 d) phases, with consistent reduction of ME and increase in AA density for each phase. On day 24, three birds per replicate were euthanized to collect digesta for nutrient digestibility and excreta samples were collected on day 40 for nutrient excretion analysis. On day 42, four birds per replicate were euthanized for carcass yield and quality evaluation. The birds' feed intake, along with calculated ME and AA levels, were used to determine nutrient intake. No interactions were observed between ME and AA densities on carcass characteristics, nutrient digestibility, and excretion (P > 0.05). Reducing ME density linearly increased breast meat yield and decreased abdominal fat, regardless of AA density (P < 0.01). Increasing AA density enhanced breast meat yield but increased white striping and woody breast scores in a linear manner (P < 0.01). Dietary treatments didn't affect ileal digestibility of crude protein and gross energy, except for improved starch digestibility with 6.0% AA density (P < 0.01). Crude fat digestibility decreased linearly with decreased ME density, while reducing ME density linearly decreased fat, calcium, copper, and manganese excretion (P < 0.01). Increasing AA density linearly increased nitrogen excretion, but reduced calcium and iron excretion (P < 0.05). Over the entire production period lower ME and higher AA density increased digestible lysine intake (mg/bird/day; P < 0.01). In summary, these results suggest that dietary ME and AA density, independently, affect carcass yield, breast meat quality, nutrient digestibility, and excretion.

Impact of storage period on hatching egg quality, extra-embryonic structures, embryo morphometry, hatchability, and Rosa 1 chick quality

Storage duration affects the biological value of hatching eggs. The study evaluated the composition and characteristics of hatching eggs from Rosa 1 hens, the morphometric traits of embryos and chicks, and hatching results based on storage time. A total of 1200 hatching eggs were divided into three groups: NS (control, non-stored), S4 (stored up to day 4), and S7 (stored up to day 7). Storage conditions were 17°C and approx. 60% relative humidity. Each group’s egg quality was measured for 30 eggs. Weight loss during storage was monitored. Lysozyme activity and viscosity were analyzed from fresh eggs and incubated eggs on days 7 and 14, using thin and thick albumen or amniotic fluid. Embryo morphometry was measured on days 7, 10, 14, and 18, and post-hatching results and the quality of one-day-old chicks were assessed. Eggs stored for 7 days (S7) had higher (P<0.05) weight loss compared to the NS group. The proportions of eggshell and yolk increased (P<0.05) after storage, and the yolk index decreased. Vitelline membrane strength was lower (P<0.001) in the S4 and S7 groups than in the NS group. The lowest (P<0.05) pH levels of thin, thick albumen and yolk were observed in the NS group. Lysozyme activity increased (P<0.001) in the thin albumen of eggs in the NS and S4 groups and the thick albumen from the NS group than in others. On day 7 of incubation, group S7 showed higher (P<0.05) lysozyme activity in thick albumen, with no activity in amniotic fluid. By day 14, lysozyme activity increased (P<0.001) in group S7’s thick albumen and S4 and S7 groups’ amniotic fluid. Viscosity was highest (P<0.05) in fresh eggs’ thin and thick albumen from group S7, but on day 7, thick albumen viscosity was lowest. On day 14, amniotic fluid viscosity was higher (P=0.009) in group S4 than in NS. Seven-day-old embryos in group S7 had lower (P=0.004) weight than others. Eye diameter in S7 embryos was also smaller on days 7 and 18. On day 10, NS group embryos had shorter body diagonal lengths. Storage up to 7 days adversely affected hatching efficiency. Storage affected the navel area of one-day-old chicks, with the highest neck length in male chicks from group S4 and the lowest in females from group S4. It is concluded that egg storage at 17°C and 60% relative humidity could be limited to 4 days to maintain hatchability and qualitative features.

Effect of dietary β-mannanase supplementation on growth performance and nutrient retention in broiler chickens fed corn-soybean meal-based diets with low energy and amino acid density

The present study was conducted to evaluate the effect of two different β-mannanases on growth performance and nutrient retention of broiler chickens fed a diet with low energy and amino acid density. A total of 312 one-day-old male broiler chickens (Ross 308) were placed in floor pens and fed a standard starter diet for 16 days. They were then randomly moved to stainless steel cages and distributed into three groups, with 13 replicates of 8 chickens each. The control group received a corn-soybean meal-based grower diet with reduced metabolizable energy by ∼100 kcal/kg and a 10-12% reduction of digestible amino acids (lysine, methionine, and threonine). Titanium oxide was added at 0.5% of diet as an indigestible marker. The other groups were fed the same diet supplemented with either β-mannanase A derived from Thermothelomyces thermophilus (100 g β-mannanase/MT grower diet) or β-mannanase B derived from Paenibacillus lentus (350 g β-mannanase/MT grower diet). The trial lasted for 7 days from d 17 to d 23, comprising 4 days of acclimatization followed by 3 days of sample collection. Final body weight (d 23), body weight gain (d 17-23), and feed intake (d 17-23) of broiler chickens did not differ among the groups. However, both β-mannanases significantly improved the feed conversion ratio during d 17-23 (P = 0.039) and nitrogen retention (P = 0.028) in broiler chickens compared to the control group. Moreover, dietary supplementation with β-mannanase A significantly increased dry matter retention (P = 0.050), organic matter retention (P = 0.028), and nitrogen-corrected apparent metabolizable energy (AMEn; P = 0.033) compared to the control group. In conclusion, supplemental β-mannanase, regardless of the product, improved the growth performance of broiler chickens by improving nutrient retention and dietary AMEn.

Effect of ethanol extract from Enterolobium cyclocarpum fruit on Leghorn chickens exposed to Eimeria.

There are concerns about residues of drugs in meat that are used to prevent coccidiosis in chickens. Natural compounds are an alternative to drugs. Two studies investigated the effect of an extract of Enterolobium cyclocarpum fruits (EEC) in the feed of male Leghorn chickens exposed to Eimeria spp. In the first experiment, the administration of EEC after infection with Eimeria spp. was investigated over 16 days. One thousand chickens were randomly housed in 20 pens of 1 m2 each. The pens were randomly assigned to each treatment. Five treatments were administered, containing 150, 300 and 450mg/kg of EEC in the feed, the fourth treatment (C) contained 0.5g/kg of a commercial anticoccidial, and the fifth treatment provided no treatment (WA). The second experiment lasted 18 days. Administration of the EEC began five days before the chickens were infected with Eimeria spp. Four hundred and eighty chickens were randomly allocated to 24 pens of 1 m2. The pens were randomly assigned to each treatment. In the second experiment, the same five treatments were tested and one additional treatment containing 300mg EEC plus 1g of polyethylene glycol (PEG)/kg of feed (E300PEG). In the experiment one chickens in the EEC treatments had lower faecal oocyst excretion (OE) on day 14 post infection with Eimeria spp., than chickens in the WA treatment (P < 0.05). A reduction in live weight gain (LWG) was observed in the EEC treatments (P < 0.05). In the second experiment, the excretion of oocysts in chickens from the EEC and E300PEG treatments on day 13 post-infection with Eimeria spp. was the same as in the C treatment and lower than in the WA treatment (P < 0.05). LWG was lower in the EEC treatments than in the C treatment (P < 0.05). However, the Chickens in the E300PEG and C treatments had similar LWG (P > 0.05) suggesting that PEG inhibits the negative effect of EEC tannins on LWG. In conclusion, the addition of EEC to chicken feed reduced both OE and LWG. Treatment with EEC and PEG (E300PEG) reduced the excretion of oocysts without negative effects on LWG.

Evaluation of the effect of nano-encapsulated Lippia origanoides essential oil extract on Salmonella serovar Enteritidis as a natural alternative to antibiotics in the poultry industry

The purpose of the present research was to evaluate the bactericidal activity of a formulation of thymol chemotype of Lippia origanoides essential oils (LOEOs) nano-encapsulated in maltodextrin against Salmonella ser. Enteritidis (SE) in an in vitro crop assay and in a prophylactic broiler chicken model using three low doses of the product: 75 ppm, 150 ppm, and 300 ppm. Two trials of each assay were conducted. Day-of-hatch male Cobb-Vantress broiler chickens were randomly allotted to one of four groups: G1) positive control group; G2) 75 ppm LOEOs group; G3) 150 ppm LOEOs group; G4) 300 ppm LOEOs group. Chicks were fed and watered ad libitum in heated brooder batteries in a controlled, age-appropriate environment. On day seven of age, all chickens were orally gavaged with 108 colony-forming units (CFU) of SE. Chickens were euthanized by exposure to CO2 for 24 hours after the SE challenge. Recovery of SE was evaluated in the liver, spleen, and ceca (including cecal tonsils). None of the three microencapsulated LOEOs doses changed SE concentration (p&gt;0.05) in the in vitro crop assay. Similarly, no significant differences in SE were observed in the organ and intestinal colonization in broiler chicken trials. Therefore, the low concentrations of the nano-encapsulated LOEOs used do not reduce SE concentration in different poultry models. Further studies are needed to optimize the formulation, delivery, models, and concentration of essential oils to control Salmonella infections in broiler chickens effectively.

Maternal Supplementation of Collagen Peptide Chelated Trace Elements Enhances Skeletal Muscle Development in Chicks.

Maternal nutrition plays an important role in regulating the growth and development of offspring. Collagen peptide chelated trace elements (PTE), as a new additive, have been proven to have a positive maternal effect on the intestinal health of offspring, but its effect on the growth anddevelopment is still unclear. This study aimed to investigate the effect of maternal PTE supplementation on the skeletal muscle development of offspring. A total of 270 breeder hens were randomly divided into 3 groups, and fed basal diet (CON), basal diet + 500mg/kg PTE (L-PTE), and 1000mg/kg PTE (H-PTE) for 8weeks. A total of 180 eggs were collected from each group for incubation, and then the hatched male chicks (6 replicates, 12 chicks/replicate) were allocated according to maternal treatment for a 14-day feeding experiment. The results showed that maternal PTE supplementation significantly increased the deposition of iron (Fe), zinc (Zn), and manganese (Mn) in the egg yolk (P < 0.05). In comparison with the CON group, the body weight (days 1 and 14), breast muscle weight (day 14), and muscle fiber density (day 14) of broilers were increased in the L-PTE group (P < 0.05). The serum creatinine (CREA) levels in 1-day-old broilers were reduced in the L-PTE group and H-PTE group(P < 0.05). Additionally, maternal PTE supplementation could upregulate the relative expression level of catalase (CAT) mRNA in breast muscle (P < 0.05). The relative mRNA levels of hemeoxygenase-1 (HO-1) and superoxide dismutase 1(SOD1) in the H-PTE group were significantly upregulated (P < 0.05). Moreover, PTE treatment upregulated the mRNA expression of skeletal muscle development-related genes (Pax7 and MyoG) and the IGF signaling pathway (mTOR, IGF-1R, and IGF-2R) (P < 0.05). In conclusion, maternal PTE supplementation may improve the growth performance and skeletal muscle development of offspring by activating the IGF signaling pathway.

Integrative 3D genomics with multi-omics analysis and functional validation of genetic regulatory mechanisms of abdominal fat deposition in chickens

Chickens are the most abundant agricultural animals globally, with controlling abdominal fat deposition being a key objective in poultry breeding. While GWAS can identify genetic variants associated with abdominal fat deposition, the precise roles and mechanisms of these variants remain largely unclear. Here, we use male chickens from two lines divergently selected for abdominal fat deposition as experimental models. Through the integration of genomic, epigenomic, 3D genomic, and transcriptomic data, we build a comprehensive chromatin 3D regulatory network map to identify the genetic regulatory mechanisms that influence abdominal fat deposition in chickens. Notably, we find that the rs734209466 variant functions as an allele-specific enhancer, remotely enhancing the transcription of IGFBP2 and IGFBP5 by the binding transcription factor IRF4. This interaction influences the differentiation and proliferation of preadipocytes, which ultimately affects phenotype. This work presents a detailed genetic regulatory map for chicken abdominal fat deposition, offering molecular targets for selective breeding.

Effects of calcium pidolate on performance, carcass traits, bone biomechanical properties and mineralisation and jejunum histomorphology in broilers

ABSTRACT 1. The current study was conducted to determine the effect of dietary calcium pidolate (CalP) on performance, slaughtering characteristics, bone biomechanical properties, mineralisation and jejunum histomorphology in male broilers. A total of 200 one-day-old Ross 308 male chicks were randomly assigned to one of four treatments as five pen replicates, each containing 10 chicks. The basal diet without CalP was formulated to supply the nutritional needs of broilers and the treatment diets contained 0.30, 0.45 and 0.60 g/kg CalP, with limestone meeting the remaining calcium requirement. 2. The addition of CalP had a quadratic effect on performance (P < 0.05) and the best performance was achieved in the group that included CalP at a dose of 0.45 g/kg but 0.60 g/kg level worsened performance. Supplementing with CalP linearly decreased carcass yield (P < 0.01) and relative breast weight (P ≤ 0.05) but the relative thigh weight increased quadratically (P < 0.05) and reached a maximum at 0.45 g/kg. 3. Tibia shear force and stress linearly increased with the use of CalP in the diet (P < 0.05). Supplementation had a quadratic effect on tibial calcium (P < 0.01), reaching a maximum at 0.30 g/kg, although tibial phosphorus levels decreased linearly (P < 0.01). 4. The effect of CalP on jejunum histomorphology fluctuated and, compared to the unsupplemented control group, the villus height/crypt depth ratio increased, while the other variables decreased (P < 0.05). Decrease in crypt depth with the addition of CalP was significant (P < 0.05). 5. Using Ca-pidolate at a rate of 0.45 g/kg in broiler diets is sufficient to increase performance and tibia strength but 0.60 g/kg level negatively affected performance. In addition, the results of jejunum histomorphology were variable, but the crypt depth decreased with CalP levels and this is an important effect. However, further research is needed to detail the effect of CalP on broilers.

Oregano essential oil and Bacillus subtilis role in enhancing broiler’s growth, stress indicators, intestinal integrity, and gene expression under high stocking density

This study investigates the role of dietary Bacillus subtilis and oregano essential oil in mitigating the effects of high stocking density on growth performance, carcass traits, physiological stress indicators, gene expression, and intestinal integrity in broiler chickens. A total of, 1250 one-day-old Ross 308 male broiler chicks were randomly allocated to five experimental groups, where each group had five replicates of 50 chicks. Group 1 (control, LSD): 15 chicks/m2 fed a basal diet without feed additive, group 2 (HSD): 20 chicks/m2 fed a basal diet without feed additive, group 3 (BHSD): 20 chicks/m2 fed a basal diet supplemented with B. subtilis (500 mg/kg diet), group 4 (OHSD): 20 chicks/m2 fed a basal diet supplemented with oregano essential oil (300 mg/kg diet), group 5 (CHSD): 20 chicks/m2 fed a basal diet supplemented with oregano essential oil and B. subtilis. At 35 days of age, there was a noticeable improvement in the growth performance of broilers fed CHSD under high stocking density through the increase in body weight gain, dressing percentage, and crude protein digestibility with a decrease in feed conversion rate compared to other groups. Adding CHSD enhanced the state of oxidation and immunity through increasing superoxide dismutase, glutathione peroxidase, and the relative weight of bursa of Fabricius, while decreasing malondialdehyde, in addition to increasing plasma triiodothyronine levels. The microbial structure and morphometric parameters improved in the group that received the CHSD compared to the other groups, where villus height and Lactobacillus population increased, whereas Escherichia coli and Clostridium perfringens population decreased. Glucose transporter 2 (GLUT2), fatty acid transporter 1 (FABP1), and amino acid transferase 1 (CAT1) gene expression levels significantly increased when feeding on oregano essential oil with B. subtilis. In conclusion, combining oregano essential oil and B. subtilis supplements mitigated the effects of high stocking density by enhancing growth performance, antioxidative status, and intestinal integrity, in addition to modifying the genetic expression of genes related to nutrient absorption.

Evaluation of protease plus a precision-biotic on body weight gain and feed conversion ratio in broilers from 0 to 42 days of age

This study aims to evaluate the effects of a protease combination with a precision biotic on body weight gain (BWG) and feed conversion ratio (FCR) of broilers from day 0 to 42. 1,400 Cobb 500 male chicks were reared on seven different diets, including an unrestricted positive control (PC–Diet 1) and a negative control (NC–Diet 2) with slightly reduced crude protein, apparent metabolizable energy (AME), and digestible amino acids. Five additional treatment diets were formulated using the negative control and varying concentrations of a protease (Diets 3-4; 33ppm and 50ppm, respectively) and in combination with a precision biotic (Diets 5-7; 33ppm + 700ppm; 50ppm + 500ppm; and 50ppm + 700ppm, respectively). The PC treatment showed significantly different feed intake and FCR compared to all other treatments in all production phases (P &lt; 0.05). There are no significant differences in non-PC treatments in all production phases for BWG and FCR (starter p=0.230 and 0.300; grower p=0.443 and 0.237; finisher p=0.450 and 0.896; overall p=0.111 and 0.497, respectively), nor is there any in terms of mortality (p=0.800). These findings may provide valuable information to producers to optimize flock performance efficiently and cost-effectively.

Effects of dietary fermented mealworm larvae and stocking density on performance, blood stress indicator and intestine parameters of broilers

The present study was conducted to evaluate the effects of the supplementation of defatted mealworm larvae meal fermented with probiotics as a new antibacterial feed additive to the diet of broilers reared under normal- (NSD) and high- (HSD) stocking density on growth performance, blood and slaughtering parameters, microorganism content and morphology of ileum and short-chain fatty acids content of ceca. A total of four hundred and fifty one-d-old Ross 308 male broiler chicks were randomly distributed into six groups of similar mean weight, each containing five replicates. Experimental treatments consisted of a 2 x 3 factorial arrangement with two levels of stocking density (12 birds/m2 as NSD and 18 birds/m2 as HSD) and three different mash diets: CONT- a corn-soybean meal-based diet containing no fermented defatted mealworm larvae meal (FDM) (0%); FDMLP- the diet obtained by supplementing DM fermented with Lactobacillus plantarum to the CONT diet (0.4%); FDMLB- the diet obtained by supplementing DM fermented with Lactobacillus brevis to the CONT diet (0.4%). HSD significantly decreased the growth performance except feed conversion ratio (FCR), carcass yields (CYs), Lactobacillus spp. content and villus height (VH) and villus surface area (VSA) of ileum and short-chain fatty acids (SCFAs) concentrations of ceca, but, increased the blood heterophil/lymphocyte (H/L) ratio and Escherichia coli content and crypt depth (CD) of ileum of broilers compared to NSD. The FDMLP and FDMLB diets significantly improved the FCR and increased final body weight (BW), BW gain, Lactobacillus spp. content and VH and VSA of ileum and SCFAs concentrations of ceca, however, reduced the blood H/L ratio and Escherichia coli content and CD of ileum of broilers when compared to the CONT diet. In conclusion, FDMLP and FDMLB can be utilized as new antibacterial feed additives in broiler diets regardless of stocking density.

The effect of high levels of Glycyrrhiza glabra powder on performance, carcass characteristics, blood parameters, immunity, intestinal microbial flora, intestinal morphology and breast muscle fatty acid profile in broilers

In order to investigate the effect of licorice medicinal plant on performance, carcass characteristics, fatty acid profile of breast muscle, intestinal microbial flora, blood constitutes and immunity of broiler chickens, an experiment using a completely randomized design with 3 treatments, 4 replications, 10 chicks per repetition and a total of 120 pieces of one-day-old male broiler chickens of commercial strain Ross 308 were performed for 42 days. Experimental treatments included three different levels of licorice (0, 300 and 400 mg/kg feed). Data was analyzed using SAS statistical software and averages were compared at the 5% probability level with Duncan's multiple range test. The results showed that although variation in feed consumption, weight gain and feed conversion ratio was not significant in any of the rearing periods (P≥0.05), the highest feed consumption, weight gain and the best feed conversion ratio was observed in the final period of chickens were fed with Diet containing 400mg/kg licorice. Also, according to the data, the best European index was related to this treatment. In addition, the use of two levels of licorice had no significant effect on carcass characteristics or intestinal microbial flora; however, the highest increase in body weight and the lowest number of Lactobacillus acidophilus bacteria were observed at the higher level of licorice. However, these high levels did not lead to a decrease in abdominal fat. According to the results obtained, different levels of licorice led to a significant reduction of harmful fats such as cholesterol, triglycerides, VLDL and LDL (P&lt;0.05). Furthermore, although the level of HDL was not significant (P≥ 0.05), its highest amount was seen at high levels of licorice. In addition, the lowest amount of total protein, albumin and globulin was observed at the level of 400 mg/kg of licorice. According to these results, although the amount of glucose was lowest its level was not significant (P≥0.05), Also, the use of this same level of licorice had no significant effect on the function of the humoral immune system in response to antigen injection (SRBC Antibody against sheep red blood cell) or antibody titer against Newcastle virus and influenza (P≥0.05). Nevertheless, according to the data, the highest antibody titer against Newcastle virus and SRBC antigen was associated with this treatment. These results also showed that high levels of licorice led to an increase in the number of Bifidobacterium. Villi width and crypt depth decreased at the high dose of licorice, but the ratio of villi length to crypt depth increased. In addition, the use of different levels of licorice could not reduce the ratio of saturated to unsaturated fatty acids compared to the control group. Therefore, based on the results of this research, it is recommended to use the level of 400 mg/kg of licorice to supplement the diet of broilers of Ross 308 strain.

Сравнително проучване на морфологичните качества и люпимостта на яйцата от чисти линии и кръстоски от общоползвателно и яйценосно направление

During the recent decades, the scientific community turned its attention towards the dual purpose lines and crosses that might offer a suitable solution for two problems in poultry breeding - the use of male chickens for meat and the use of female chickens for rearing in alternative types of systems for egg production. Hence, a study with four groups of birds: a dual purpose cross „Salmon“, a dual purpose purebred line „BB“, a laying line „L“ and a laying hybrid line „ISA-Brown“ was conducted. The aim was to compare the morphological traits, as well as the fertility and the hatchability of the eggs, obtained from „ISA-Brown“, compared to the dual purpose „Salmon“ reared at IAS-Kostinbrod, and the local dual purpose and laying lines involved in its creation. As a result of the conducted research, we can conclude that the selection for high performance, larger eggs and the presence of heterosis in hybrids has to some extent a positive influence on most of the morphological traits determining the quality of the eggs produced. In addition, negative consequences for their hatchability, embryo survival and some morphological parameters such as increased width of the egg and increased diameter of the yolk were also observed. On the other hand, in the stock hybrids, compared to the purebred lines and the dual purpose crosses, this can also be considered as a sign of deterioration of the nutritional quality of the eggs.

The effects of early feeding with different pre-starter diets on growth performance, morphological development and microorganism content of the small intestine of broiler chicks

The present study was conducted to compare the effects of feeding 2 different pre-starter diets to broiler chicks at 2 different times on growth performance, slaughtering parameters, morphological development of the small intestine segments and the microorganism content of the ileum of broilers. A total of 600 day-old Ross 308 male broiler chicks were randomly distributed into 5 treatment groups with 5 replicates of 24 chicks each. The experimental treatments included: SD10: broiler chicks were fed a corn-soybean meal-based starter diet for 0-10 days; 1PSD5: chicks were fed a first pre-starter diet based on corn-soybean meal for 0-5 days, afterwards they were fed a starter diet based on corn-soybean meal for 5-10 days; 1PSD10: chicks were fed the first pre-starter diet for 0-10 days; 2PSD5: chicks were fed a second pre-starter diet based on rice-soybean meal for 0-5 days, afterwards they were fed a starter diet based on corn-soybean meal for 5-10 days; 2PSD10: chicks were fed the second pre-starter diet for 0-10 days. Broilers were fed a basal diet based on corn and soybean meal until the end of the experimental period. The 1PSD5, 1PSD10, 2PSD5 and 2PSD10 treatments significantly increased final body weight (BW) and BW gain, decreased feed intake (FI) and improved feed conversion ratio (FCR) of broilers from 0 to 42 day compared to the SD10 treatment. The lowest FI and the best FCR of broilers during the period of 0 to 42 day were obtained by the 2PSD5 treatment. The 1PSD5, 1PSD10, 2PSD5 and 2PSD10 treatments significantly enhanced the hot- and cold-carcass yields and villus heights (VHs) and decreased crypt depths of small intestine segments of broilers on day 42. However, the experimental treatments did not significantly affect the the E.coli and Lactobacillus contents of ileum of broilers on day 42. In conclusion, feeding of chicks with the pre-starter diet based on rice-soybean meal supplemented with enzyme complex and synbiotic for 0-5 days was a more effective treatment in terms of performance especially FI and FCR, carcass yields and VHs of small intestine segments of broilers.

Coated oregano essential oil and cinnamaldehyde compounds supplementation improves growth performance, enhances immune responses, and inhibits cecal Escherichia coli proliferation of broilers.

Plant essential oils are unstable due to high volatility and easy oxidation, while microencapsulation provides a potentially effective strategy for increasing the stability of natural essential oils and preserving their function. This study examined the effects of feeding coated oregano essential oil and cinnamaldehyde (COEC) compounds on growth, immune organ development, intestinal morphology, mucosal immune function, and the cecal microbiota populations of broilers. Three hundred one-day-old male Arbor Acres broiler chicks were organized into 5 groups: 1) negative control fed basal diet alone (NC), 2) positive control receiving basal diet plus 50mg/kg of chlortetracycline (CTC), 3) basal diet plus 150mg/kg COEC (COEC150), 4) plus 300mg/kg COEC (COEC300), and 5) plus 450mg/kg COEC (COEC450). The supplement trial was continued for 42 d. The results showed that CTC, COEC300, and COEC450 treatments decreased the feed conversion ratio of broilers both in the starter and whole experiment phases, increased the height of jejunal villi at 21 d and the number of goblet cells and IgA-producing cells at 21 or 42 d compared with NC group (P < 0.05). Members of the COEC300 treatment group had a higher thymus weight index and jejunum length index than birds of NC or CTC groups at 21 d (P < 0.05). CTC and all COEC treatments decreased malondialdehyde content in jejunal mucosa at 42 d (P < 0.05). The population of Escherichia coli (E. coli) in the cecal digesta at 21 d was lower in the CTC, COEC300, and COEC450 treatment groups compared with the NC group (P < 0.05). In contrast to the CTC group, COEC supplementation dose-dependently accelerated body weight gain, improved jejunal morphology, decreased malondialdehyde content in jejunal mucosa, increased numbers of jejunal goblet cells and IgA-producing cells, and decreased the E. coli population in cecal digesta at 21 or 42 d (P < 0.05). Thus, we concluded that feeding broiler chickens with 300 or 450mg/kg in antibiotic-free diets can improve growth performance, enhance immune responses, and inhibit the proliferation of cecal pathogenic bacteria.

Effect of Heat Stress on the Expression of Circulating Cyto(chemo)kine and Inflammatory Markers in Broiler Chickens Selected for High- or Low-water Efficiency.

Water scarcity is a current, significant global concern that will only increase under the pressure of climate change. Improving water efficiency of poultry is a new and promising area to help temper agriculture's future impact on fresh water availability. Here, we explored the effects of acute heat stress (HS) on circulating stress and inflammatory markers in 2 lines of broilers divergently selected for water efficiency. Male chicks from low (LWE) and high water efficient (HWE) lines were raised in 12 environmental chambers (2 pens/chamber, 6 chambers/line, 20 birds/pen) under normal conditions until day 28. On day 29, birds were subjected to thermoneutral (TN, 25 °C) or HS (36 °C) conditions, resulting in four treatments (2 lines × 2 environmental conditions). After 3 h of HS, whole blood was collected (8 birds per line × environment) and analyzed for target gene expression and plasma cytokine levels. Data were analyzed by 2-way ANOVA, with line, environment, and their interaction as main factors, and means were compared using Tukey's multiple range test. Gene expression of heat shock protein (HSP) 27, HSP70, interleukin (IL)-6, IL-18, c-reactive protein (CRP), tumor necrosis factor-α (TNFα), C-C motif chemokine ligand 4 (CCL4), CCL20, nucleotide-binding domain, leucine-rich repeat (NLR) family pyrin domain containing 3 (NLRP3), NLR family CARD domain containing 5 (NLRC5), and NLR family member X1 (NLRX1) were increased by HS, with no differences between the lines. HSP70, IL-10, and NLRC3 were lower in the HWE as compared to the LWE lines. Additionally, there were interactive effects between line and environment for HSP90, IL-4, and CCL4, where HS induced HSP90 expression in the LWE only, and IL-4 and CCL4 in HWE only. Arginine vasopressin (AVP) gene expression was significantly lower in the whole blood of the HWE line; however, plasma protein levels were not different. Overall, most of the effects seen on cyto (chemokines) and inflammatory markers were due to acute HS, with only a few genes differentially regulated between the lines. This likely indicates that the divergent selection for water efficiency for four generations did not elicit changes in inflammation and stress molecular signatures.