The effect of dietary crude protein (CP) and additives on odor flux from meat chicken litter was investigated using 180 day-old Ross 308 male chicks randomly allocated to five dietary treatments with three replicates of 12 birds each. A 5 × 3 factorial arrangement of treatments was employed. Factors were: diet (low CP, high CP, high CP+antibiotic, high CP+probiotic, high CP+saponin) and age (15, 29, 35 days). The antibiotic used was Zn bacitracin, the probiotic was a blend of three Bacillus subtilis strains and the saponin came from a blend of Yucca and Quillaja. Odorants were collected from litter headspace with a flux hood and measured using selective ion flow tube mass spectrometry (SIFT-MS). Litter moisture, water activity (Aw), and litter headspace odorant concentrations were correlated. The results showed that low CP group produced lower flux of dimethyl amine, trimethyl amine, H2S, NH3, and phenol in litter compared to high CP group (P < 0.05). Similarly, high CP+probiotic group produced lower flux of H2S (P < 0.05) and high CP+saponin group produced lower flux of trimethylamine and phenol in litter compared to high CP group (P < 0.05). The dietary treatments tended (P = 0.065) to have higher flux of methanethiol in high CP group compared to others. There was a diet × age interaction for litter flux of diacetyl, 3-hydroxy-2-butanone (acetoin), 3-methyl-1-butanol, 3-methylbutanal, ethanethiol, propionic acid, and hexane (P < 0.05). Concentrations of diacetyl, acetoin, propionic acid, and hexane in litter were higher from low CP group compared to all other treatments on d 35 (P < 0.05) but not on d 15 and 29. A high litter moisture increased water activity (P < 0.01) and favored the emissions of methyl mercaptan, hydrogen sulfide, dimethyl sulfide, ammonia, trimethyl amine, phenol, indole, and 3-methylindole over others. Thus, the low CP diet, Bacillus subtilis based probiotic and the blend of Yucca/Quillaja  saponin were effective in reducing the emissions of some key odorants from meat chicken litter.

Arginine activity in broiler diets can be supplied by L‐arginine (Arg), guanidinoacetic acid (GAA) and L‐citrulline (Cit), all of which are commercially available. This study was conducted to assess the effects of Arg source and level on broiler performance, nutrient digestibility and carcass parameters. Day‐old Ross 308 cockerels (n = 768) were assigned to one of eight dietary treatments using a completely randomized design: normal protein (NP), low protein deficient in Arg (LP) and LP with two levels of either Arg (0.238% and 0.476%), GAA (0.309% and 0.618%) or Cit (0.238 and 0.476%). The LP was 5 percentage points lower in protein level than the NP. Wheat, sorghum, soya bean meal, canola meal, and meat and bone meal‐based diets were fed over three feeding phases to 6 replicate floor pens with 16 birds each. Compared to NP, birds fed LP had reduced feed intake (FI, p < 0.001), reduced body weight gain (BWG, p < 0.001) and increased feed conversion ratio (FCR, p < 0.001) from day 0 to day 35. Additions of Arg or Cit to the LP at both levels resulted in increased BWG and reduced FCR (p < 0.05). Birds fed LP with GAA added had lower FCR (p < 0.05) but not higher BWG (p > 0.05) compared with the LP observed from day 0 to day 35. Supplementation of Arg, Cit and the low level of GAA to LP resulted in increased carcass yield, bone length, diameter and ash (p < 0.05) but did not increase ileal energy or nitrogen digestibility (p > 0.05). The findings indicate that Cit is an efficacious source of Arg activity in Arg‐deficient diets.

A 3-factor, 3-level Box-Behnken design was used to investigate the interaction effect of dietary digestible lysine (dLys, 9.5, 10.5, 11.5 g/kg), apparent metabolizable energy (AMEn, 12.77, 13.19, 13.61 MJ/kg) and available P (avP, 3.0, 4.0, 5.0 g/kg) levels on performance and amino acid (AA) digestibility of Ross 308 male broilers (n = 1,050) from d 14 to 34. The design consisted of 15 treatments each replicated 5 times with 12 birds per replicate. On d 34, 3 birds were sampled from each pen to collect ileal digesta (pooled per pen) to analyze AA. Response surface was fitted by first-, second-, or third-degree polynomial regressions in JMP statistical software v. 12.0.1. Feed intake (FI), weight gain (WG) and feed conversion ratio (FCR) were affected by dLys (linear and quadratic, P < 0.01), AMEn (linear, P < 0.01) and AMEn × avP (P < 0.01). Increased dLys increased FI but increased AMEn decreased FI in the birds fed the low-avP diet. However, when the avP level in the diet was increased, FI decreased to 13 MJ/kg AMEn and remained constant thereafter. Increased dLys increased WG whereas an increase in AMEn decreased WG in the birds fed the low-avP diet but had no effect on WG in those fed the high-avP diet. Increased dLys decreased FCR whereas increased AMEn decreased FCR in the birds fed the low-avP diet but had no effect on FCR in those fed the high-avP diet. Increased dLys increased breast yield percentage (linear, P < 0.01 and quadratic, P < 0.05) whereas increased AMEn decreased breast yield percentage (linear, P < 0.01). Dietary levels of dLys or avP had positive, linear effects on apparent ileal digestibility (AID) of methionine (P < 0.01) and threonine (P < 0.01) but had no effect on other AA (P > 0.05). These results indicate that increasing dLys levels above current industry standard would improve broiler performance irrespective of AMEn or avP levels of the diet.

A study was conducted with Hy-Line Brown laying hens to examine the effects of reduced protein diet, deficiency of arginine (Arg), and addition of crystalline Arg, citrulline (Cit) and guanidinoacetic acid (GAA) as substitutes for Arg. Hen performance, egg quality, serum uric acid, liver and reproductive organ weights, and energy and protein digestibility were measured using a completely randomized design with 5 treatments. Treatments were a standard diet (17% protein diet; SP), a reduced diet (13% protein diet deficient in Arg; RP) and RP with added Arg (0.35%, RP-Arg), GAA (0.46% equivalent to 0.35% Arg, RP-GAA) or Cit (0.35%, RP-Cit) to the level of SP. It was hypothesized that performance would decrease with Arg deficient RP diet and the addition of GAA or Cit in RP would allow birds to perform similar or greater than Arg-added RP treatment. The experiment was conducted from 20 to 39 wk of age but the treatment effect was seen only after 29 wk of age. The birds offered RP had reduced egg and albumin weights ( P < 0.01), lower yolk color score ( P < 0.01), lower protein intake and excretion ( P < 0.01) than those offered SP. When Arg or Cit were added to RP to make them equivalent to SP, feed intake (FI) and egg production were not different than those of RP ( P > 0.05). The birds offered RP-GAA decreased FI and egg production ( P < 0.01) compared to those offered RP. The addition of Arg, Cit or GAA to the RP had no effect on egg quality parameters, protein and energy digestibilities ( P > 0.05). However, birds offered the RP-Cit diet tended to have higher Haugh unit ( P = 0.095) and lower shell breaking strength ( P = 0.088) compared to all other treatments while those offered RP-GAA had higher energy digestibility ( P < 0.05) than all other groups but RP. The limited performance response of hens fed RP with added Arg, GAA, or Cit may be due to deficiency of some other nutrients in RP such as phenylalanine, potassium or non-essential amino acids and other components of soybean meal in the diet.

A study was conducted to determine the performance, egg quality, and liver lipid reserves of laying hens exposed to ranges contaminated with Ascaridia galli. Sixteen-week-old Lohmann Brown laying hens (n = 200) were divided into 4 treatments with 5 replicates containing 10 hens per pen. Hens of treatment 1 [negative control (NC)] ranged on a decontaminated area, and hens of treatments 2 (low infection) and 3 (medium infection) ranged on areas previously contaminated by hens artificially infected with 250 and 1,000 embryonated A. galli eggs, respectively. The hens of treatment 4 [positive control (PC)] ranged on areas previously contaminated by hens artificially infected with 2,500 embryonated A. galli eggs, and in addition these hens were orally inoculated with 1,000 embryonated eggs. Results indicated that hens of the medium infection group had a higher number of intestinal A. galli worms and A. galli eggs in the coprodeum excreta (43.9 ± 4.0 and 3,437 ± 459 eggs/g) compared to hens of the low infection group (23.8 ± 4.0 and 1,820 ± 450 eggs/g) (P < 0.01) and similar worm counts to PC hens (34.4 ± 4.0 and 2,918 ± 474) (P > 0.05). Egg production, egg mass, feed intake, and feed conversion ratio (FCR) were not affected by A. galli infection (P > 0.05). Egg quality parameters (egg weight, shell reflectivity, shell weight, shell thickness, shell percentage, shell breaking strength, deformation, albumen height, Haugh unit, and yolk score) were not affected by A. galli infection (P > 0.05). Highly infected hens had lower liver lipid content (2.72 ± 0.51 g) compared to uninfected hens (4.46 ± 0.58 g, P < 0.01). The results indicate that exposure to ranges contaminated with A. galli resulted in infection of the ranging hens, but this did not affect egg production or egg quality. Infection with A. galli lowered the liver lipid reserves of the host significantly, suggesting infected hens use more energy reserves for maintenance and production.

No abstract

Heat stress causes significant economic losses in the broiler industry. Dietary supplementation of arginine (Arg) and citrulline (Cit) might increase the performance of broilers raised under warm temperature due to vasodilation effects. This study investigated the effects of L-Arg or L-Cit supplementation in broilers fed a reduced protein wheat-based diet deficient in Arg under thermoneutral (NT) and cyclic warm temperature (WT). Ross 308 cockerels ( n = 720) were randomly allocated to 4 dietary treatments with 12 replicates of 15 birds per pen from d 7 to 21. The 4 treatments were: normal protein (NP), i.e., 22.3% and 20.9% crude protein in grower and finisher, respectively; reduced protein (RP), i.e., 2.5% lower protein and deficient in Arg; and RP supplemented with 0.28% Arg (RP-Arg) or 0.28% Cit (RP-Cit). A factorial arrangement of treatments was applied during the finisher phase (21 to 35 d). Factors were: diet (4 diets above); and temperature, NT (24 °C) or cyclic WT (33 ± 1 °C for 6 h per day) with 6 replicate pens per treatment. During 7 to 35 d and 21 to 35 d, the birds fed the RP diet had lower body weight gain (BWG) and higher FCR compared to the NP diet ( P < 0.01). The addition of Arg or Cit to RP decreased FCR compared to RP ( P < 0.01). During 21 to 35 d, the birds exposed to WT had lower feed intake (FI), lower BWG ( P < 0.001) but similar FCR ( P > 0.05) compared to birds exposed to NT. Diet by temperature interactions were not observed for performance parameters during the period of WT ( P > 0.05). On d 35, the RP-fed birds had a lower yield of thigh and drumstick, higher fat pad, lower femur ash, and breaking strength but similar serum uric acid level and higher nitrogen digestibility on d 21 compared to those offered NP ( P < 0.05). Supplementation of Arg or Cit to RP resulted in increased femur ash on d 35 ( P < 0.05). Thus, feeding the NP diets is necessary to maintain growth performance in broilers regardless of the temperature conditions.

Plant extracts (PE) are gaining increased attention as potential alternatives to in-feed antimicrobials (AM) due to their known antimicrobial activities. This study was conducted to examine the potential of PE, a microencapsulated product composed of eugenol and garlic tincture as an alternative to AM-agent on performance and intestinal health in broilers under necrotic enteritis (NE) challenge. A total of 960 day-old mixed-sex Cobb 500 chicks were randomly distributed to 48-floor pens with 6 treatments replicated 8 times with 20 birds each. The 6 treatments were as follows: UC, unchallenged control; CC, challenged control; PE, challenged group plus PE; AM, challenged group plus AM; FAP, challenged group plus a full dose of AM with PE; HAP, challenged group plus a half dose of AM with PE in starter, grower and finisher phases. Birds in the challenged groups were inoculated with Eimeria spp. on d 9 and Clostridium perfringens on d 14. The body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR), and livability of birds were compromised, and intestinal lesions and mortality were increased ( P < 0.05) by NE challenge, illustrating a successful clinical NE challenge. Birds fed AM had higher BWG and FI, and lower FCR, mortality, and intestinal lesions compared to the CC group ( P < 0.05). Birds fed PE had improved FCR ( P < 0.05) and livability (5.8%) in an overall period compared to the CC group. On d 16, PE supplementation reduced ileal lesion scores in only male birds ( P < 0.05). Birds fed PE had decreased Eimeria maxima and Eimeria acervulina oocyst counts in caecal content ( P < 0.05). Birds fed PE had decreased Escherichia brunetti and total oocyst counts in caecal content, and E . acervulina oocyst counts in ileal content in only female birds ( P < 0.05). On d 35, PE supplementation reduced variation of BW in both male and female birds and increased yellowness (b∗ value, 14.4%) in the thigh. These findings suggest the potential of PE supplementation in diets to improve the performance and intestinal health of birds under clinical NE as indicated by improved FCR, livability, uniformity, reduced ileal lesions, oocyst counts and increased skin yellowness. However, the protective effect of PE may not be apparent in the presence of AM in the feed.