Rosiane de Souza Camargos

This study aimed to evaluate probiotics supplementation in diets for semi-heavy layers hens and their effects on the internal quality of eggs stored under refrigeration for different periods. 210 Hisex Brown® laying hens aged 30 weeks were distributed in a completely randomized design wIth six treatments, and seven replications,. The experimental diets were offered for 112 days. The experimental diets were: Control: control diet, without the inclusion of probiotics and feed efficiency-enhancing additives; CP: positive control feed with the inclusion of a feed efficiency-enhancing additive (Halquinol antibiotic inclusion at 60g kg-1); C+100: control feed with the inclusion of 100 g t-1 of a product based on Bacillus subtilis (Bacillus subtilis guaranteed level 2.0*106 CFU/g); C+150: feed with the inclusion of 150 g t-1 of the Bacillus subtilis-based product; C+200: feed with the inclusion of 200 g t-1 of Bacillus subtilis-based product; C+250: feed with the inclusion of 250 g t-1 of Bacillus subtilis-based product. A total of 588 eggs collected in the experimental plots were used (2 eggs per plot), and storage times at room temperature were 0, 5, 10, 15, 20, 25, and 30 days and were analyzed for internal egg quality. Probiotic supplementation did not influence the internal quality of the eggs. The storage time under refrigeration influenced the percentage and quality of the eggs' internal components and weight loss, with worse results in eggs stored for longer.

This study aimed to evaluate the effectiveness of different LED lamp colors (red and white) on the productive performance and egg quality of light laying hens. A total of 144 birds of the commercial strain Hy-Line® W-36 aged 44 weeks were distributed in a completely randomized design with two treatments (red and white LEDs) and 12 replicates, totaling 24 experimental plots with six birds each. Treatment means were compared by the F Test (5% probability) on the statistical software SISVAR. This study found that laying hens under red LED lamps showed a trend of greater egg production bird-1 day-1 (%) (p = 0.084), average egg weight (g) (p = 0.0826), egg mass (p < 0.05), and shell thickness (mm) and height (mm) (p < 0.01), whereas birds under white LED light showed better yolk color (p < 0.05). It is concluded that red LED illumination increases egg production and quality in light laying hens.

The use of antibiotics in poultry farming has been associated with bacterial resistance in humans, leading to a ban on their inclusion in chicken diets. Therefore, the objective was to evaluate the effects of probiotics and β-mannanase on the growth performance and intestinal health of broiler chickens challenged by Eimeria maxima and Clostridium perfringens. For this, 2100 one-day-old male Ross 308 chicks were used. The treatments were as follows: T1—Negative control (NC) unchallenged birds; T2—Positive control (PC) challenged with E. maxima + C. perfringens; T3—PC + Antibiotic (Enramycin 8%-125 g/ton); T4—PC + β-mannanase (Hemicell^HT; 300 g/ton); T5—PC + probiotic (Protexin^TM; 150 g/ton); T6—PC + β-mannanase + probiotic. Significant differences (p < 0.05) were observed from 1 to 42 days in the variables body weight, body weight gain and feed intake, and the NC treatment presented higher values compared to the PC and PC + probiotic groups. The villus/crypt ratio in the duodenum increased in the PC + β-man + prob treatment, differing from the NC, PC and PC + probiotic (p < 0.05) treatments. The use of β-mannanase, probiotics or both together is effective to mitigate the effects of production challenges, through the maintenance of the intestine by modulating action on the cecum microbiome and intestinal morphometry.

Indirect calorimetry (IC) is a widely used method to study animal energy metabolism by measuring gas exchange. The accuracy of IC depends on detecting variations in signals reflecting the metabolic response, which can be challenging due to measurement noise and external factors. This study proposes a methodology to validate IC systems, including an easy-to-use spreadsheet for data computing, to verify accuracy and detect whole-system leaks. We conducted a recovery test using a simulation of CO₂ dynamics in MS Excel and injecting a known CO₂ concentration into four respirometry chambers. The thought flow rate of CO₂ was observed and compared to the expected rate from the simulation. Data filtering and computing, including a detailed calculation of signals calibration, Bartholomew transformation, and noise reduction, was developed to obtain the gas exchange and heat production parameters using an open-circuit IC system. The results from the recovery test in our system show that the proposed methodology is accurate and precise. The proposed methodology and recovery test can be used to standardize the validation of IC systems together with adequate data computing, providing accurate measurements of animal energy metabolism in different environmental conditions and energy utilization from feeds.

Objective: The objective of this study was to describe a methodological procedure to quantify the heat production (HP) partitioning in basal metabolism or fasting heat production (FHP), heat production due to physical activity (HPA), and the thermic effect of feeding (TEF) in roosters.Methods: Eighteen 54-wk-old Hy Line Brown roosters (2.916±0.15 kg) were allocated in an open-circuit chamber of respirometry for O2 consumption (VO2), CO2 production (VCO2), and physical activity (PA) measurements, under environmental comfort conditions, following the protocol: adaptation (3 d), ad libitum feeding (1 d), and fasting conditions (1 d). The Brouwer equation was used to calculate the HP from VO2 and VCO2. The plateau-FHP (parameter L) was estimated through the broken line model: HP = U×(R–t)×I+L; I = 1 if tR; Where the broken-point (R) was assigned as the time (t) that defined the difference between a short and long fasting period, I is conditional, and U is the decreasing rate after the feed was withdrawn. The HP components description was characterized by three events: ad libitum feeding and short and long fasting periods. Linear regression was adjusted between physical activity (PA) and HP to determine the HPA and to estimate the standardized FHP (st-FHP) as the intercept of PA = 0.Results: The time when plateau-FHP was reached at 11.7 h after withdrawal feed, with a mean value of 386 kJ/kg0.75/d, differing in 32 kJ from st-FHP (354 kJ/kg0.75/d). The slope of HP per unit of PA was 4.52 kJ/mV. The total HP in roosters partitioned into the st-FHP, termal effect of feeding (TEF), and HPA was 56.6%, 25.7%, and 17.7%, respectively.Conclusion: The FHP represents the largest fraction of energy expenditure in roosters, followed by the TEF. Furthermore, the PA increased the variation of HP measurements.

Objective: This study aimed to evaluate the effect of the ad libitum and restricted feeding regimen on fasting heat production (FHP) and body composition.Methods: Twelve Hubbard broilers breeders were selected with the same body weight and submitted in two feeding regimes: Restricted (T1) with feed intake of 150 g/bird/d and ad libitum (T2). The birds were randomly distributed on the treatments in two runs with three replications per treatment (per run). The birds were adapted to the feed regimens for ten days. After that, they were allocated in the open-circuit chambers and kept for three days for adaptation. On the last day, oxygen consumption (VO2) and carbon dioxide production (VCO2) were measured by 30 h under fasting. The respiratory quotient (RQ) was calculated as the VCO2/VO2 ratio, and the heat production (HP) was obtained using the Brower equation (1985). The FHP was estimated throughout the plateau of HP 12 hours after the feed deprivation. The body composition was analyzed by dual-energy X-ray absorptiometry scanning at the end of each period. Data were analyzed for one-way analysis of variance using the Minitab software.Results: The daily feed intake was 30 g higher to T2 (p<0.01) than the T1. Also, the birds of the T2 had significatively (p<0.05) more oxygen consumption (+3.1 L/kg0.75/d) and CO2 production (+2.2 L/kg0.75/d). That resulted in a higher FHP 359±14 kJ/kg0.75/d for T2 than T1 296±17.23 kJ/kg0.75/d. In contrast, the RQ was not different between treatments, with an average of 0.77 for the fasting condition. In addition, protein and fat composition were not affected by the treatment, while a tendency (p<0.1) was shown to higher bone mineral content on the T1.Conclusion: The birds under ad libitum feeding had a higher maintenance energy requirement but their body composition was not affected compared to restricted feeding.