Performance Of Male Broilers Research Articles

Effect of plant extracts derived from thyme on male broiler performance

The effect of dietary thyme-oil extract (TOE) supplementation on immune functions of broilers were assessed by feeding graded levels (50, 100, 200, or 400 ppm) of TOE to male broiler chicks during a 42-d feeding trial compared with negative- or positive-control diets. Dietary control treatments included a negative-control diet with no feed-additive supplementation and 2 positive-control groups supplemented with either virginiamycin or zinc bacitracin. In total, 300 1-day-old Ross × Ross male broilers were randomly assigned to 6 dietary treatments that consisted of 5 replicates of 10 birds each. On d 21 and 42, 2 birds from each replicate were killed by cervical cutting to measure the relative weights of spleen and bursa of Fabricius. At 25 d of age, chicks were injected with 0.5 mL of 10% SRBC suspension. Broilers fed with 200 ppm of TOE had heavier weights of bursa of Fabricius than those fed other dietary treatments at d 42 of age. Furthermore, dietary inclusion of 100 ppm of TOE resulted in higher (P < 0.05) total immunoglobulin response in primary antibody titer against sheep erythrocytes compared with other dietary treatments. On the other hand, diet modifications had no significant effect on blood leukocyte subpopulations and heterophil-to-lymphocyte ratio. These results suggest that dietary supplementation with TOE, especially at the level of 100 ppm, can improve immunological responses of broiler chicks.

Changing the incubation temperature during embryonic myogenesis influences the weight performance and meat quality of male and female broilers

Eggs of broilers were initially incubated at 37.8°C, then at 38.8°C (group H) and 36.8°C (groupL) between embryonic days 7 to 10 (time A) and days 10 to 13 (time B) and further incubated at 37.8°C until hatching. The chicks were fattened until day 35 and then slaughtered. The effect of treatment, time, and sex and their interactions on carcass and meat quality traits were determined. No significant impact of the "treatment time" was analysed, but "treatment" and "sex" and their interactions influenced (P < 0.05) the different parameters. After hatching, group L broilers were heavier (P < 0.05), followed by slower growth compared to group H chicken. At slaughter day, body, carcass, and leg weights of group H broiler were higher (P < 0.05) and yield results lower (P<0.05) compared to group L animals. pH, drip loss, shear force, and lightness values of group H broiler breast muscles were higher (P < 0.05) and grill loss and redness values lower (P < 0.05) compared to group L Musculus pectoralis superficialis (MPS). Body, carcass, MPS, and leg weights, leg yields and grill loss and lightness values of the male broiler were higher (P < 0.05) and drip loss results lower (P<0.05) than the female birds. Male group H broiler showed lower (P < 0.05) carcass and MPS yields compared to the control and group L males, whereas females group H birds had higher (P < 0.05) carcass and MPS weights and lower leg yields (P < 0.05) than the female group L animals. The study shows that an increasing incubation temperature during early embryogenesis positively influences the growth and carcass traits of the broilers, accompanied with a partly negative impact on meat quality (drip loss, shear force, lightness). The growth effects were sex-dependent, as significant weight differences could be only found in female broilers. The results indicate that incubation temperature alteration influences molecular mechanisms in the muscle and other tissues with an impact on growth after hatch.

Effect of feeding an encapsulated source of butyric acid (ButiPEARL) on the performance of male Cobb broilers reared to 42 d of age

The objective of this research was to determine the optimal level of an encapsulated butyric acid (ButiPEARL) based on the performance of male Cobb broilers reared to 42 d of age and to investigate its effects on intestinal morphology. Experiment 1 (EXP 1) consisted of 4 treatments with 12 replicate pens that contained 45 broilers, and Experiment 2 (EXP 2) consisted of 6 treatments with 8 replicate pens that contained 50 broilers. Birds were weighed by pen on d 0, 21, 35, and 42. In EXP 1, the treatments were as follows: 1) control (C); 2) C + 100 g ButiPEARL/ton; 3) C + 200 g ButiPEARL/ton; and 4) C + 300 g ButiPEARL/ton. In EXP 2, the treatments were identical to EXP 1, with 2 additional treatments: 5) C + 400 g ButiPEARL/ton and 6) C + 500 g ButiPEARL/ton. In EXP 1, two 42-d-old broilers per pen were randomly selected for duodenal and jejunal tissue collection. Only the samples from the broilers fed the C or 300 g ButiPEARL treatments were analyzed for histology in EXP 1. For EXP 2, on d 21 and 35, two broilers per pen were randomly selected for duodenal, jejunal, and ileal tissue collection. For EXP 1 and 2, BW gain increased linearly with increasing butyric acid levels (P < 0.027 and P < 0.001, respectively). For EXP 1 and 2, feed conversion linearly improved with increasing butyric acid from 0 to 42 d (P < 0.001 and P < 0.001, respectively). In EXP 1, there were no differences in any intestinal morphology at 42 d between broilers fed the C or 300 g ButiPEARL treatments. In EXP 2, there were no differences in villus height at 21 or 35 d of age with any level of butyric acid. Based on the results of this research related to BW gain and feed conversion, the recommended optimum dosage level for ButiPEARL in broilers reared to 42 d of age is up to 500 g/ton.

Effects of color of light on preferences, performance, and welfare in broilers

Broiler houses are mainly lit by fluorescent light. With the expected continued increase in energy prices, the interest in less energy consuming light sources is growing. The light-emitting diode (LED) is an energy-saving alternative. The aims of the present 2 studies were to examine 1) the preference for LED color temperature and effects on behavior, and 2) effects of LED color temperature on performance and welfare of male broilers (Ross 308). Two color temperatures were investigated: neutral-white (4,100 K) and cold-white (6,065 K). First, 6 groups of 6-day-old chicks were housed in pens consisting of 2 lightproof compartments with a pop-hole between allowing chicks to move freely between compartments. Number of broilers in each compartment and their behavior were recorded every 15 min on 6 d. A preference for 6,065 K was found (P < 0.001). On d 16, 28, and 34, more time was spent in the 6,065 K treatment (P < 0.03), whereas indifference between treatments was found on d 4, 10, and 22 (P > 0.07). Second, each of the 2 light conditions was applied to 6 groups of 75 chicks. BW and feed consumption were registered weekly. On d 34, we scored gait, foot pad dermatitis, and hock burns in 15 individuals/pen. At slaughter (d 35), cold carcass weight was recorded from all individuals, while yields of different body parts were collected from 9 individuals/group. Broilers from the 6,065 K treatment were 67.4 ± 19.2 g heavier on the day of slaughter (P = 0.0009), whereas no difference was found at other ages (P > 0.12). Feed intake was found to be similar for the 2 treatments (P = 0.52). Pectoralis minor was 4.1 ± 1.9 g heavier in the 6,065 K treatment (P = 0.03). There was no difference between the light treatments in any of the welfare parameters. We conclude from the results that of the 2 color temperatures examined, the most suitable for use in commercial broiler houses is 6,065 K.

Effects of organic, inorganic, and nano-Se on growth performance, antioxidant capacity, cellular and humoral immune responses in broiler chickens exposed to oxidative stress

The present study was designed to compare different sources of Selenium (Se) on growth performance, antioxidant capacity, cellular and humoral immune responses of male broilers subjected to oxidative stress. In a completely randomized design, 320 broilers were assigned to a 2×4 factorial arrangement comprising 4 replicates of 10 birds per each. Broilers were divided in two groups for oxidative stress; a group as control (no oxidative stress) and the other one was peritoneally received tert-butyl hydro peroxide (tert-BHP) as oxidative stress inducer. Birds in each level of oxidative stress were received either supplemented Se diet (CON) or diets supplemented with 0.3mg/kg nano-Se (NAN), organic Se (ORG), and inorganic Se (INO). Sources of Se, oxidative stress, and their interaction had no effect on the feed intake, daily body gain and feed conversion ratio (P>0.05). Se supplementation increased glutathione (GSH) content and glutathione peroxidase (GSH-Px) activity compared to the control group (P<0.05). However, birds in oxidative stress had lower glutathione (GSH) content and GSH-Px activity as compared to non-stressed ones. Se supplemented groups had lower malondialdehyde (MDA) concentrations compared to the control groups (P<0.05), and birds on oxidative stress conditions had higher MDA level as compared to non-stressed birds. The IgM and IgG levels were significantly increased in NAN group compared to CON and other experimental groups (P<0.05). The highest serum IgG and IgM concentrations were recorded for non-stressed birds received nano-selenium and organic selenium. Birds in oxidative groups had lower foot swelling response value as compared to non-oxidative groups only at 24h following the phytohemagglutinin-P (PHA-P) injection (P<0.05). The oxidative condition decreased the lymphoid organs weight compared to non-oxidative condition. These increases in antioxidant enzyme activities have been considered as a protective response against oxidative stress. It was concluded that supplementation of diet with 0.30mg/kg of different sources of Se increased the antioxidative capacity of broiler chicken under oxidative stress and nano-Se effect was higher than organic or inorganic source.

Effects of step-up and step-down phytase regimens on performance and processing yields of male broilers from 1 to 35 d of age

An experiment was conducted to evaluate increasing or decreasing concentrations of dietary phytase on growth performance and processing yields of male broilers from 1 to 35 d of age. Treatments consisted of a positive control, a negative control (NC; less 0.14% Ca, 0.13% nonphytate P, and 0.03% Na), and 6 additional treatments based on the NC supplemented with phytase. Treatments 3 through 5 consisted of the NC diet supplemented with 500 phytase units (FTU)/kg of phytase in the starter phase that was either continued throughout the remainder of the study (treatment 3) or increased to 1,500 FTU/kg beginning in the finisher (treatment 4) or grower (treatment 5) phases. Treatment 6 had 1,500 FTU/kg of phytase throughout the study. Treatments 7 and 8 had 1,500 FTU/kg in the starter and decreased to 500 FTU/kg in the finisher or grower phases, respectively. At 35 d of age, broilers fed diets containing 1,500 FTU/kg of phytase had increased BW gain compared with birds fed diets formulated to contain 500 FTU/kg of phytase. Increasing phytase concentration between the starter and grower phases or decreasing phytase concentration between the grower and finisher phases negatively affected FCR from 1 to 35 d of age. Phytase supplementation did not affect weight and yield of carcass characteristics. Therefore, dietary phytase concentration should not be varied throughout production for optimum growth performance.

Sunflower meal and enzyme supplementation of the diet of 21- to 42-d-old broilers

The objective of this study was to evaluate the performance of male broilers between 21 and 42 days of age fed diets supplemented with an enzyme blend (EB) and containing graded levels of sunflower meal (SFM). In total, 1920 male Cobb broilers were distributed according to a randomized block experimental design in a 4 x 3 factorial arrangement (four SFM dietary levels vs. three feed formulations) with eight replicates of 20 birds each. Dietary SFM inclusion levels were 0, 8, 16, and 24%. Feed formulation included one negative control diet (NC) formulated to supply broiler nutritional requirements, considering EB nutritional matrix values; a diet formulated as the first one, but with the addition of 0.5% EB (NC+EB); and the third diet (positive control - PC) was calculated to supply broiler requirements. Feed intake, weight gain, feed conversion ratio, and carcass parameters were evaluated. There was no effect of EB dietary supplementation on the evaluated performance or carcass parameters (p > 0.05). Increasing dietary addition of SFM reduced weight gain and worsened feed conversion ratio (p > 0.05). The best EEI was obtained with the NC+EB diet containing 8.0% SFM.

Effects of black cumin seed (Nigella sativa L.), a probiotic, a prebiotic and a synbiotic on growth performance, immune response and blood characteristics of male broilers

This study was performed to investigate and compare the effect of different feed additives on growth performance, slaughter parameters, immune response, leukocyte profile and blood biochemical parameters of broilers. A total of 350 day-old male broiler chickens (Ross 308) were randomly assigned to seven treatments with five replicates each (10 chickens per replicate). Chickens were fed either a corn-soybean meal basal diet (control) or the basal diet supplemented with 5g/kg black seed (BS1), 10g/kg black seed (BS2), 20g/kg black seed (BS3), 1g/kg probiotic (Pro), 1g/kg prebiotic (Pre) or 1g/kg synbiotic (Syn). Average body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR) of broilers were determined during the starter (0 to 10 days), grower (11 to 28 days) and finisher (29–42 days) periods, and also for the total experimental period (0–42 days). Three chickens per replicate were randomly selected to evaluate a cutaneous basophil hypersensitivity reaction to phytohaemagglutinin-P (PHA-P) on days 35 and 36. Blood samples (2 samples per replicate) were taken for measuring antibody responses (days 28 and 42), and also for hematological and biochemical analysis (day 42). After 6 weeks, BWG was higher for Syn-fed chickens compared with control group (P<0.05). From 0 to 42 days, FCR was improved by diets BS2, Pro and Syn by approximately 6.3, 6.3 and 7.3% respectively, compared to that of the control group (P<0.05). The toe web swelling, as cell mediated response to PHA-P, in the chickens fed diets BS3 and Syn was respectively 30.5 and 27.1% greater than in chickens fed control diet (P<0.05). All diets, except diets BS1 and BS2, increased primary antibody response against sheep red blood cell (SRBC) at 28 days (P<0.05). Moreover, broilers fed diets BS3, Pro and Syn showed the higher secondary anti-SRBC titers and lower plasma triglyceride, cholesterol and low-density lipoprotein cholesterol levels at 42 days (P<0.05). Other measured parameters, including FI, slaughter parameters, leukocyte profile, heterophil to lymphocyte ratio and plasma glucose and high-density lipoprotein cholesterol levels were not affected by the treatments (P>0.05). In conclusion, dietary supplemented with probiotic, synbiotic or 10 to 20g/kg black seed improved FCR of broilers and improved plasma lipid profile and antibody-mediated immunity. These findings justify further investigations to evaluate the efficacy of these additives before field application.

Effects of cereal type, enzyme and sodium butyrate addition on growth performance, carcass traits and intestinal morphology of broilers

A 2 × 2 × 2 factorial arrangement was conducted to evaluate the effects of cereal type (corn vs. wheat), enzyme supplementation (0 or 0.4 g/kg diet), and sodium butyrate addition (0 or 2 g/kg diet) on growth performance, carcass traits and intestinal morphology of male broilers from 10 to 42 d. A total of 600 male Arbor Acres chickens were assigned to eight dietary treatments in a completely randomized design, providing five replicate pens per treatment. Diets were formulated to meet or exceed NRC nutrient recommendations. When compared with birds fed corn-based diets, chickens fed wheat-based diets had inferior weight gain (1978 vs. 1807 g, p 0.05) on the relative weights of the proventriculus, gizzard, pancreas, liver and heart. Cereal type had a significant (p < 0.05) effect on intestinal morphology, including villus height and crypt depth. Jejunal villus height (p < 0.05) and crypt depth (p < 0.01) were improved by sodium butyrate addition. In conclusion, the results of this experiment showed that enzyme and sodium butyrate addition, especially to the wheat based diet, improve growth performance.

Growth performance, digestibility, immune response and intestinal morphology of male broilers fed phosphorus deficient diets supplemented with microbial phytase and organic acids

The poultry industry is currently facing several challenges, including the environmental impact of poultry production, bird health and immunity, and the safety of poultry products. This experiment was conducted to evaluate the effect of phytase supplementation and organic acids (alone or in combination) on growth performance, nutrient digestibility, tibia ash, immunity, and gut morphology of male broiler chickens (Ross 308). The birds were allocated to 5 dietary treatments: (1) positive control diet (PC) with adequate amount of available phosphorus (4.9 and 4.4g/kg in the starter and grower period, respectively); (2) negative control diet (NC) with a low amount of available phosphorus (3.9 and 3.4g/kg in the starter and grower period, respectively); (3) NC plus 0.2% of a commercial organic acid (Salkil; Sal); (4) NC plus 500 phytase unit/kg diet (Phy); (5) NC plus Salkil and phytase (Sal+Phy). Each treatment had 5 pen replicates of 20 birds. The starter (0–14d) and grower (15–28d) maize–soybean meal based diets were fed ad libitum in mash form. The results showed that overall, birds fed the Phy+Sal diet and birds fed the NC diet had the highest and lowest (P<0.001) live weight gain (50.80g/bird/d vs 39.68), feed intake (74.78g/bird/d vs. 64.69) and feed conversion ratio (1.47 vs. 1.63), respectively. Broilers fed the NC diet had the lowest crude protein and ether extract digestibility (0.7751 and 0.7949, respectively), which were improved (P<0.001 and P=0.010, respectively) by the addition of Phy (0.8506 and 0.8645, respectively) or Phy+Sal (0.8858 and 0.8561, respectively) to the NC diet. Tibia ash was improved (P<0.001) in Sal-fed broilers (374.3g/kg) compared with NC (341.6g/kg), but it was still lower than other treatments (PC, Phy and Phy+Sal). Addition of Phy or Phy+Sal to the NC diet improved villus height and villus height/crypt depth ratio in the duodenum, jejunum and ileum of broilers compared with broilers fed the PC diet. Broilers fed Phy+Sal showed higher (P<0.001) IgG (2.27) in the primary and also higher (P<0.001) total Ig (7.84) and IgG (5.74) in the secondary response compared with all other treatments. In conclusion, concurrent supplementation of phytase and organic acids improve productive performance, bone mineralization, intestinal integrity, and immune response of broilers fed diets low in available phosphorous.

Apilarnil reduces fear and advances sexual development in male broilers but has no effect on growth

1. An experiment was conducted to determine the possibility of stimulating sexual development at an early age in male and female broiler chickens by administration of apilarnil, a natural bee product, in the pre-pubertal period. 2. From 28 to 55 d of age, birds were given apilarnil orally. The effects of low (2.5 g/bird) and high (7.5 g/bird) doses of apilarnil on growth performance, testicular weight, secondary sexual characteristics, blood lipids, testosterone and fearful behaviour were evaluated. 3. Apilarnil administration did not cause a positive effect on growth performance of male and female broilers suggesting that apilarnil did not have an anabolic effect. 4. Apilarnil administration suppressed blood glucose and cholesterol. 5. Birds receiving apilarnil remained immobile for a shorter period in a tonic imobiliy test and showed less home-cage avoidance responses suggesting a lower level of fearfulness. 6. Increases in testicular weight, testosterone concentration and comb growth in males receiving apilarnil implied that it stimulates the sexual maturation at an early age. However, a similar stimulation of secondary sexual characteristics was not observed in females.

The effect of peppermint essential oil and fructooligosaccharides, as alternatives to virginiamycin, on growth performance, digestibility, gut morphology and immune response of male broilers

With the increasing concerns over food safety during these years, there has been an intense effort for substituting (eliminating) antibiotic growth promoters in poultry feeds. Therefore, in order to investigate the effect of natural alternatives for antibiotics, an experiment was conducted to examine the effect of virginiamycin, a prebiotic (Fructomix), and peppermint (Mentha piperita) essential oil on productive performance, digestibility, intestinal morphology and immune response of broilers. A total of 240 Ross 308 male broilers were randomly (completely randomized design) allotted to five treatments, with four replicates per treatment (12 chickens per pen). Birds were offered either a maize-soybean meal basal diet (control, CON) or the basal diet supplemented with 200mg/kg virginiamycin (VM); 200mg/kg peppermint oil (PO1); 400mg/kg peppermint oil (PO2); or 500mg/kg Fructomix (FM). After 6 weeks, daily live weight gain and feed intake were higher (P<0.001) for VM-fed birds compared with other groups. Feed conversion ratio was better (P=0.039) in chicks fed the VM (1.74), and PO1 diet (1.75) compared with birds in the CON (1.84) and PO2 (1.86) groups. Primary antibody titers against sheep red blood cell were higher (P<0.001) in broilers fed FM (6.37) compared with other groups. At 21d of age, crude protein digestibility was higher (P=0.001) in PO1 group (0.8645) compared with other groups except VM (0.8505). Finally, higher ether extract digestibility (P=0.040) was detected in birds fed VM (0.8831) compared with PO2 (0.7940), and FM (0.7561) fed birds. In duodenum, villus height: crypt depth was higher (P=0.008) in VM supplemented group (7.07) in comparison with other groups. In conclusion, this study showed that neither PO nor FM could be suggested as effective alternative for VM.

Effect of Sex and Dietary Organic Zinc on Growth Performance, Carcass Traits, Tissue Mineral Content, and Blood Parameters of Broiler Chickens

Zinc (Zn) is an essential mineral for animal development and function. A study was carried out to evaluate the effect of sex and dietary organic zinc (OZ) on growth performance, carcass traits, tissue mineral content, and blood parameters of broiler chickens. A total of 240 1-day-old male and 240 female broiler chicks (Cobb × Cobb) were assigned to two dietary levels of OZ (2 × 2 factorial) with six replicates per treatment (20 birds/replicate pen). The OZ supplementation levels were 0 and 25 ppm. Results showed that OZ supplementation did not affect the growth performance of male and female broilers, but the males showed significantly better (P < 0.05) growth performance than females did. Similarly, OZ supplementation did not affect the thickness of both the back and thigh skin of male and female broilers; however, males had thicker skin than females. Dietary OZ supplementation did not affect collagen contents in the skin and meat samples. Male broilers had higher skin collagen contents than females, but no sex difference was found in meat collagen contents. OZ supplementation did not affect the shear force values of skin and meat samples. Male broilers had higher shear force values of back skin than females, but not in the meat samples. Dietary OZ supplementation increased (P < 0.05) the thigh meat Zn content in both sexes. The plasma Ca content was significantly (P < 0.05) increased by dietary OZ supplementation; however, other blood parameters were not affected by dietary OZ supplementation. Males had higher plasma glucose and cholesterol content than females. It is concluded that dietary OZ supplementation at the level of 25 ppm does not affect the growth performance and skin quality of broiler chickens but increases the Zn content in thigh meat and Ca content in plasma of broiler chickens. Male broilers had better growth performance and skin quality than females.

Effect of different lysine levels on Arian broiler performances

An experiment was conducted to evaluate the performance and carcass yield of Arian male broilers fed diets (starter and grower) with different levels of lysine requirements, high lysine (120% National Research Council, NRC), medium lysine (110% NRC), standard (100% NRC) and low lysine (90% NRC) in a completely randomized experimental design. All diets were isocaloric and isonitrogenous. In broilers receiving 120% of NRC Lysine, body weight in 42 d significantly increased by 248 g compared with standard lysine diet. Feeding broilers with high lysine diets (120% NRC) significantly increased feed intake and body weight gain (22–42 and 0–42 day of age) compared with standard group (P<0.05). Body weight was significantly difference in all of weeks of trail (P<0.05). Lysine levels had no effect on feed conversion ratio. This study showed that increasing lysine level (120% NRC) in diet significantly increased abdominal fat pad, gizzard and heart weight compared with standard group (P<0.05).The results of this study suggest that additional lysine at the level of 120% of NRC in starter and grower diets optimized body weight gain in Arian broiler, whereas reductions in lysine level reduced growth and live weight.

Effect of added l-glutamic acid on male broiler performance when using wheat- or corn-based diets and 2 different anticoccidials

Glutamic acid may play a role in skin integrity, which could influence carcass quality. A study was undertaken to determine if supplementing l -Glu would influence the live performance and carcass quality of broilers when using different cereal and anticoccidial sources. The study consisted of 2 cereal sources (wheat or corn), 2 l -Glu levels (0 or 1.75%), and 2 anticoccidial sources (monensin or halofuginone), for a total of 8 treatments with diets meeting or exceeding nutrient recommendations for essential amino acids and energy for the starter (0 to 17 d of age), grower (18 to 43 d of age), and finisher (44 to 48 d of age) feeds. Each dietary treatment was fed to 4 replicate pens of birds containing 33 chicks/pen at the time of placement. Adding l -Glu to the starter diets with monensin improved FE regardless of the cereal source; however, the opposite was true for halofuginone. Feed efficiency at d 43 and 48 was improved with added Glu, although during the grower period, cereal and anticoccidial sources did influence FE independently. Bruising of wings and drumsticks, and back skin problems were influenced by anticoccidial source. Adding Glu reduced drumstick deformities, especially when halofuginone was used in the diets. Yields of breast fillets and tenders were significantly greater for corn-fed vs. wheat-fed broilers. Breast fillet yield (g) was lower for broilers fed halofuginone. Drumstick yield (%) was increased with the addition of Glu to the diet. Supplementing the diet with Glu reduced carcass defects, which may reflect the need for Glu in connective tissue formation during rapid growth. The benefit of Glu may depend on the anticoccidial and cereal sources used.

Effect of dietary lipid sources on production performance of broilers

A study was conducted to determine the influence of different dietary lipid sources and inclusion levels on production performance of male broilers. Eight isoenergetic (15.1 MJ AME/kg DM) and isonitrogenous (223 g CP/kg DM) diets were formulated, using high oleic sunflower oil (HO), sunflower oil (SO), fish oil (FO) and tallow (T) at a 30 g/kg and 60 g/kg dietary inclusion level. Eight hundred (800), day-old Ross 788 broiler males were randomly allocated to the eight treatments (n = 100) and were further subdivided into four replicates/treatment (n = 25). All birds receive a standard commercial diet for the first 14 days, where-after the experimental diets were fed for 28 days. Feed intake and body weights were recorded weekly, while mortalities were recorded and dead birds weighed daily. Mortalities were brought into consideration during the calculation of average daily feed intake (g feed/bird/day) and feed conversion ratio (g feed/g body weight gain). Contrary to saturated fatty acids (T), the inclusion of unsaturated fatty acids (HO, SO, FO) at a higher level (60 g/kg) resulted in a significantly improved FCR. It seems that the optimum dietary inclusion level of saturated fatty acids is lower (30 g/kg) than that of unsaturated sources.

Effect of dietary mannan oligosaccharide with or without oregano essential oil and hop extract supplementation on the performance and slaughter characteristics of male broilers

The effects of some alternative feed additives for antibiotic growth promoters on performance and some slaughter characteristics were examined in broilers fed wheat-soya based basal starter and finisher diets. A total of 2160 one-day-old male broiler chicks were randomly allocated to six groups with six replicate pens per treatment. The treatments were the basal diet (Control), and the basal diet supplemented with an antibiotic growth promoter (AGP); a prebiotic, mannan oligosaccharide (Bio-Mos, MOS); an essential oil of oregano (Herb-Mos Oregano, HMO); a plant extract of hop (Herb-Mos Hops, HMH) or a mixture of Herb-Mos Oregano and Herb-Mos Hops (HMOH). There were significant effects of dietary treatments on body weight and feed conversion ratio in the 0 - 21 d period, and on body weight and feed consumption in the 0 - 42 d period. The addition of all experimental additives to the diet resulted in significantly higher body weights as compared to the control treatment at both 21 and 42 days of age. Feed intakes were significantly different between the treatments at 0 - 21 d and 22 - 42 d periods, but not during the 0 - 42 d period. However, during the 0 - 21 d period the broiler chickens that received diets supplemented with AGP, MOS, HMO, HMH and HMOH had significantly better feed conversion ratios than the control group, but this pattern was not sustained during the finisher period (22 - 42 d). Mortality rate, hot carcass yield and relative weights of the small intestines, pancreas, abdominal fat and bursa of fabricius were not affected by experimental treatments. The HMH supplementation increased relative liver weight. These results showed that AGP, MOS and herbal feed additive (HMO, HMH, HMOH) supplementation to a diet provided significant advantages on broiler growth performance through a 42-d growth period. However, the combined supplementation of HMO and HMH did not exert either synergistic or additive benefits on the live performance of the broilers. These results also proved that MOS, HMO, HMH and HMOH improved broiler live performance as well as an AGP in both the starter and through the grower period. Furthermore, outstanding advantages were evidenced for the HMH treatment in particular. Therefore, the MOS, HMO, HMH and HMOH performance enhancer feed additives of natural origin may be considered as potential substitutes for AGP in broiler diets.

Effects of different nutritional plans on broiler performance

An experiment was carried out at the Department of Animal Science of the Federal University of Viçosa, Brazil, to evaluate the effects of different nutritional plans on the performance of male and female Ross broilers. A completely randomized experimental design with a 6x2 factorial arrangement (six nutritional plans x two sexes) with six replicates of 20 birds per experimental unit was applied. The nutritional plans adopted for males and females included 3, 5, or 28 feeds, and the other 3 plans included 28 feeds containing 92.5, 100, and 107.5% of digestible lysine requirements established according to a mathematical model developed exclusively for Ross broilers. The results showed that the tested 28-feed feeding programs are equivalent, and allow similar performance as compared to 3- and 5-feed feeding programs. Based on the lysine levels included in the different nutritional plans, it was possible to fit the equations: Y = -0.0079x + 1.2435 (R² = 0.981) for males and Y = -0.0084x + 1.1925 (R² = 0.978) for females, where "Y" is digestible lysine level (%) and "x" is average age in days. These equations are specific for multiple-phase feeding programs. The performance of male and female broilers fed the lysine levels established by the mathematical models was similar as to that of birds fed the other nutritional plans. This demonstrates that it is possible to determine broiler lysine.

Effects of elutriation and sieving processing (Elusieve) of distillers dried grains with solubles on the performance and carcass characteristics of male broilers

SUMMARY A technique combining elutriation (air classification) and sieving was developed to remove some of the fiber component of distillers dried grains with solubles (DDGS). Herein, DDGS were sieved into 4 different sizes: large, medium, small, and pan. Fiber was removed from the 3 largest sizes by elutriation via an aspirator, whereby air was blown through the different size categories at a predetermined velocity as the product was falling from the sifter, through the aspirator, and into a collection container. This air movement resulted in a portion of the lighter fiber component being blown into a separate chamber of the respirator and thus into a separate container. The DDGS product obtained by mixing the material that underwent this procedure was called “big DDGS.” The pan material, which was in the smallest size category, has a lower fiber concentration and thus underwent no elutriation (pan DDGS). Four different dietary treatments with 12 replicates each were fed to Ross × Ross 308 male broilers from hatch until 42 d of age. A corn- and soybean meal-based diet without DDGS served as the control (treatment 1); treatment 2 had conventional DDGS included at a concentration of 8% (unmodified DDGS); treatment 3 consisted of 8% big DDGS inclusion (partially modified DDGS, PMD), and the fourth treatment consisted of 8% pan DDGS (ED). Final BW was observed to be superior for the birds fed the ED-based diets compared with the BW of those birds fed the control diet and the PMD-based diet. However, contrast analysis showed a significant difference in BW (P = 0.08), with birds fed ED-based diets exhibiting higher BW compared with birds fed unmodified DDGS-based diets. Feed intake was numerically higher for birds fed ED-based diets compared with all other treatments and was significantly greater for birds fed ED-based diets vs. those fed PMD-based diets for the 0- to 42-d period. No other differences were found in bird performance or carcass traits. Results showed some improvement of DDGS via the use of this technology, judging by a marginal improvement in final BW.

Efficiency of a prebiotic and a plant extract alone or in combination on broiler performance and intestinal physiology

A 36-d trial was conducted to evaluate two potential alternatives to antibiotic growth promoters in broilers. The products tested were a prebiotic (PROFEED®) and a plant extract (XTRACT™). Ross male broiler performance and digestive tract function responses were studied. To evaluate the effect of these potential alternatives alone or in combination, seven diets were tested: positive control avilamycin 10 ppm (PC); negative control antibiotic-free (NC); NC + PROFEED® 600 ppm (P); NC + XTRACT™ 100 ppm (X); NC + PROFEED®/XTRACT™ 600/100 ppm (XPH); NC + PROFEED® /XTRACT™ 450/75 ppm (XPM); NC + PROFEED®/XTRACT™ 300/50 ppm (XPL). From 22 to 36 d of age, body weight gain (BWG) was improved by P, X, and XPM compared with NC (P &lt; 0.05). Throughout the trial, broilers fed PC, P, X and XPL had a better feed conversion ratio (FCR) than those fed NC (P &lt; 0.1). No relevant negative effect was observed for the parameters relative to the digestive tract function: ileal histomorphometry, anaerobic sulphite-reducing bacteria count (ASR), intestinal and caecal pH, caecal volatile fatty acids production (VFA) and litter score (LS). With the higher mixture dose (XPH), no improvement in broiler performance was observed, suggesting no synergistic effect of the two additives. Key words: Broiler, antibiotic growth promoter, plant extract, prebiotic