Cecal microbial composition and serum concentration of short-chain fatty acids in laying hens fed different fiber sources.

The intestinal microbiota is widely recognized as an integral factor in host health, metabolism, and immunity. In this study, the impact of dietary fiber sources on the intestinal microbiota and the production of short-chain fatty acids (SCFAs) was evaluated in Lohmann White laying hens. The hens were divided into four treatment groups: a control diet without fiber, a diet with wheat bran (mixed fibers), a diet with insoluble fiber (cellulose), and a diet with soluble fiber (pectin), with six replicates of four hens each.

Impact of increased pre-start diet density on broiler chick behavior, corticosterone levels, and performance responses under cold stress during early life.

This study assessed the effects of increased pre-start diet density on the metabolism, crop filling, and overall performance of broilers under cold stress during their initial 14 days of life. Using 576 one-day-old Cobb500 male chicks from 27-week-old breeders, the experiment employed a 2 × 2 arrangement, varying thermal conditions (thermoneutrality or cold stress at 18 °C for 8 h) and pre-start diet composition (21.5% crude protein, 2970 kcal/kg or 22.

Transfer of Caffeine and Its Major Metabolites to Chicken Eggs.

This study aimed to determine whether the eggs of laying hens fed caffeine contain this compound and its primary metabolites (theophylline, theobromine, and paraxanthine). Laying hens were distributed into four experimental groups fed rations containing 0 (control), 150, 300, or 450 μg/g of caffeine. For residual analysis, six eggs per group were collected after 4, 8, and 12 weeks.

Effects of cold stress on physiologic metabolism in the initial phase and performance of broiler rearing.

This study aimed to investigate the effects of 8 h of cold stress (18 °C) every day in broiler chicks during the first 7 days of rearing on crop filling analysis, yolk sac consumption, digestive and immune organs weights, and physiological metabolism at seven days and performance between 1 and 35 days. Cobb500 male broiler chickens (n = 274) were randomly assigned to two treatments. The treatments consisted of varying environmental temperatures during the first week post-housing.

Sanitization at different times after floor egg collection for hatchability, microbiological quality, and performance of broilers.

In this study, the effects of egg type and sanitization time on eggshell and yolk sac microbiological quality, hatchability, and broiler performance at 7 and 35 d of age were evaluated. A total of 3,440 eggs from a commercial flock Cobb500 were randomly assigned in a 2 × 2 factorial scheme, separated by the type of egg (clean nest or floor) and eggs sanitization at 30 or 120 min after collection, totaling 4 treatments. After hatching, 312 male chicks were randomly selected and distributed according to treatment.

Floor eggs: Hatchability, microbiological analysis, and effects of post-hatch use of ceftiofur on performance of broiler chicks.

The present study aimed to determine the effects of egg type (nest clean or floor eggs) on eggshell microbiological, hatching performance, chick quality, yolk sac microbiology, and the interaction between egg type and post-hatch use of ceftiofur on broiler performance at 7, 14, 21, 28 and 35 days. A total of 2500 fertile eggs were obtained from a commercial flock of Cobb Slow® broiler breeders. Half of the eggs were collected directly from the floor, and the other half were collected from the nests.

Feed form and nutritional level for rearing growing broilers in thermoneutral or heat stress environments.

The present study aimed to investigate the effects of different physical forms of feed and feeding programs on nutrient digestibility and performance of grower-finisher broilers under thermoneutrality or thermal stress. Three experiments were conducted using male broiler chickens (n = 720) aged 19-42 d. The design of two of the experiments was fully randomized in a 2 × 2 factorial arrangement with two forms of feed (mash and pellet) and two nutritional levels (13.

Short communication: Effects of breeder age and pre-placement feed on IgY concentration in egg yolk and chick serum.

Breeder age and pre-placement feed are factors that can affect broiler performance during grow out. This study evaluated the effects of breeder age (29 and 55 weeks old) on IgY transference to egg yolk in addition to the effects of breeder age (29 and 55 weeks old) and pre-placement feed (with or without), in a factorial arrangement, on IgY concentration in chick serum. Forty-eight eggs were collected from a breeder flock and considered the experimental units.

Runting and Stunting Syndrome in Broiler Chickens: Histopathology and Association With a Novel Picornavirus.

Runting stunting syndrome (RSS) in commercial chickens has been reported worldwide, and although several studies have attempted to clarify the cause and describe the lesions, there are gaps in knowledge of the epidemiology, pathogenesis, and etiology. The study objective was to use commercial chicks naturally affected by RSS to describe the histologic changes of RSS in all segments of the small intestine in chicks of different ages and to identify viral gene sequences in affected chicks and their association with histologic lesions. Chicks lacking clinical signs but from the same houses and from unaffected houses were used as controls.

Relative bioavailability of manganese in relation to proteinate and sulfate sources for broiler chickens from one to 20 d of age.

The objective of this study was to evaluate the relative bioavailability (RB) of manganese (Mn) proteinate compared to Mn sulfate for broilers fed a diet based on corn and soybean meal for 20 d. The diets of 1,350 male Cobb broilers were supplemented with 0, 35, 70, 105, or 140 mg of Mn/kg of feed in the form of Mn sulfate or Mn proteinate. Weight gain, feed intake, feed conversion, bone strength, and Mn concentration in the tibia and liver, as well as the concentration of type I collagen in the tibia, were evaluated.

Effects of Caffeine on Egg Quality and Performance of Laying Hens.

This study's objective was to determine the effects of caffeine intake at various levels, incorporated in the layers' food, on performance and egg quality of hens. A total of 576 hens, aged 56 weeks, were used. The layers were fed rations containing 0 (control), 150, 300, or 450 ppm of caffeine for 12 weeks.

Determination of the residue levels of nicarbazin and combination nicarbazin-narasin in broiler chickens after oral administration.

The depletion times of the anticoccidial nicarbazin administered individually and of nicarbazin and narasin administered in combination were evaluated by determining the presence and levels of 4,4'-dinitrocarbanilide (DNC), the marker residue for nicarbazin, and narasin residues in the muscle tissues of broiler chickens subjected to a pharmacological treatment. A high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was used. The results showed the presence of all anticoccidial residues; however, the DNC levels were higher when the nicarbazin was administered individually than when it was used in association with narasin throughout the experimental period.

Evaluation of the Presence and Levels of Enrofloxacin, Ciprofloxacin, Sulfaquinoxaline and Oxytetracycline in Broiler Chickens after Drug Administration.

The depletion times of enrofloxacin and its metabolite ciprofloxacin as well as sulfaquinoxaline and oxytetracycline were evaluated in broiler chickens that had been subjected to pharmacological treatment. The presence and residue levels of these drugs in muscle tissue were evaluated using an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method that was validated in this work. The results showed the presence of all antimicrobial residues; however, the presence of residues at concentrations higher than the drugs' maximum residue limit (MRL) of 100 μg kg-1 was found only during the treatment period for oxytetracycline and until two days after discontinuation of the medication for enrofloxacin, ciprofloxacin and sulfaquinoxaline.