Modeling nutritional and performance factors that influence the efficiency of weight gain in relation to excreted nitrogen in weaning piglets.

One of the most debated topics in pig production is the need to study, understand and change the production system in order to improve nutrient efficiency, becoming more environmentally friendly. The nitrogen excretion has highly deleterious effects on the environment, and it is necessary to develop tools that help to reduce the excretion of this compound without compromising productivity. Therefore, two models were generated to estimate the efficiency of weight gain in relation to excreted nitrogen in post-weaning piglets. Data for testing these models were obtained from previous master and PhD studies carried out at the Federal University of Rio Grande do Sul, Animal Science Laboratory using piglets in the post-weaning phase with results for performance and digestibility. The database that was constructed was composed of raw data from 10 studies carried out between 2000 and 2016, on a total of 726 piglets weaned at ages between 17 and 28 days, and to which 62 different treatments were applied. An exploratory analysis of the data was done by evaluating scatter plots and histograms, and variables representing different treatments were used in a stepwise multiple linear regression analysis, with the F-test used as the selection criterion. Two models were generated that either considered the nitrogen retained or not, to estimate the ratio between weight gain and excreted nitrogen using generalized linear model procedure. The authors analyzed the behavior of each variable to evaluate whether the equation generated was biologically coherent. Weight gain, dry matter intake, nitrogen intake, metabolizable energy intake, retained nitrogen and urinary nitrogen were all significant (P<0.001) variables in model I, and in model II the variable fecal nitrogen was also included. The models had high coefficients of determination (R2 of model I and II were 0.9013 and 0.8271, respectively), and the nitrogen ingested variable was the one that most strongly influenced growth efficiency. When the retained nitrogen variable was removed from the model, there was a reduction in the fit of the equations. It was possible to conclude that both of the two models generated could be applied and the amount of nitrogen ingested had the greatest influence on growth efficiency related to nitrogen excretion.

Comparison between a commercial blend of functional oils and monensin on the performance and microbiota of coccidiosis-challenged broilers.

The aim of the study was to evaluate the effects of a cashew nut shell oil and commercial castor oil blend (CNSL-Castor oil) on the performance and microbiota of broiler chickens with and without coccidiosis challenge. A total of 864 one-day-old male chicks (Cobb) were randomly distributed to receive 6 treatments (8 pens/treatment; 18 chicks/pen) in a 3 × 2 factorial, with 3 additives (control [non-additives], 100 ppm sodium monensin, or 0.15% CNSL-Castor oil blend), and 2 levels of coccidiosis challenge at 14 D of age (unchallenged or inoculated by gavage with 1 mL of solution containing oocysts sporulated with Eimeria tenella, Eimeria acervulina, and Eimeria maxima). No differences in productive performance were observed among treatments in the pre-challenge period and in unchallenged birds (P > 0.05). Seven-days post-challenge, birds receiving monensin performed better than birds in the positive control group (non-additive and challenge) or in the CNSL-Castor oil group (P > 0.05). However, 14 D post-challenge, birds supplemented with CNSL-Castor oil presented higher weight gain and better feed conversion (P > 0.05), without any change in feed intake (P > 0.05). During the accumulated period (1 to 42 D of age), the live weight, weight gain, and feed intake did not differ between the CNSL-Castor oil and monensin groups, both of which presented higher values than the positive control. Lactobacillus spp. and Clostridium perfringens numbers were increased in the challenged birds (P < 0.05). CNSL-Castor oil supplementation reduced Clostridium cluster XIV, C. perfringens, and S. aureus, compared with the monensin and control groups (P > 0.05). In addition, the CNSL-Castor oil group presented the highest number of Lactobacillus spp. copies, followed by the monensin and positive control groups (P > 0.05). Thus, monensin and CNSL-Castor oil effectively minimized the impact of coccidiosis at different times. While monensin acts as an antimicrobial, CNSL-Castor oil modulates the intestinal microbiota with antimicrobial action against gram-positive bacteria, mainly C. perfringens and S. aureus.

Effects of rice protein coatings combined or not with propolis on shelf life of eggs.

Although eggs are an excellent protein source, they are a perishable product. Many methods exist to extend shelf life of food and one of them is the use of protein coatings that may be combined with antimicrobial substances, as propolis. The effectiveness of rice protein coatings plus propolis on maintaining interior quality and eggshell breaking strength of fresh eggs was evaluated during storage at 20°C for 6 wk. Egg quality was assessed by weight loss, Haugh unit (HU), albumen pH, yolk index (YI), shell strength, and scanning electron microscopy in uncoated eggs (control treatment) and eggs coated with rice protein concentrate and propolis at 5 or 10%. The HU and YI were higher in coated eggs (P < 0.001). Weight loss increased (P < 0.001) during long-term storage. Uncoated eggs showed the highest weight loss (5.39%), whereas rice protein (4.27%) and rice protein plus propolis at 5% (4.11%) and 10% (4.40%) solutions were effective in preventing weight lost (P < 0.001). Uncoated eggs had the worst (P < 0.001) HU (58.47), albumen pH (9.48), and YI (0.33) after 6 wk of storage. The eggs coated with rice protein and rice protein plus propolis presented results with similar intern quality between them during all the storage period. Scanning electron microscopy demonstrated a lower surface porosity in coated eggshell, indicating that the use of the coating may provide a protective barrier against the transfer of gases and moisture. In conclusion rice protein and propolis treatments helped to maintain egg quality for a longer time compared to uncoated eggs. These could be a viable alternative for maintaining the internal quality of fresh eggs during long-term storage at room temperature.

Effect of functional oils on the immune response of broilers challenged with Eimeria spp.

Infection with Eimeria sp. results in the activation of multiple facets of the host immune system; the use of phytogenics can modulate the inflammatory response and improve the performance of the challenged animal. The aim of this study was to evaluate the effect of a commercial blend of cashew nut shell liquid (CNSL) and castor oil on the immune response of broilers challenged with coccidiosis. A total of 864 one-day-old male chicks (Cobb 500) were randomly distributed into six treatment groups (8 pens/treatment and 18 chicks/pen) in a three-by-two factorial design with three additives: control (non-additive), 100 ppm of monensin or 0.15% CNSL-castor oil. Challenge status was determined twice at 14 days of age. Unchallenged birds were inoculated by gavage with oocysts sporulated with Eimeria tenella, Eimeria acervulina and Eimeria maxima. Although the positive control (non-additive and challenged) and CNSL-castor oil treatment groups exhibited similar variation in weight gain (ΔBWG) compared to unchallenged birds fed without additives, the variation observed in birds fed diets containing CNSL-castor oil was associated with a higher maintenance requirement and not feed efficiency. In the second week after infection, ΔBWG of the CNSL-castor oil treatment group did not significantly change compared to the other treatment groups. At days 7 and 14 post-challenge, there was a higher excretion of oocysts in the control group, whereas the CNSL-castor oil and monensin groups did not differ. The CNSL-castor oil group exhibited increased gene expression of interferon (IFN), interleukin 6 (IL-6) and tumor necrosis factor (TNF), while the control group exhibited increased expression of cyclooxygenase (COX) and IL-1. The heterophils/lymphocyte ratio was low for the monensin treatment group. The unchallenged birds that received monensin treatment presented higher gene expression of IFN, COX and IL-1 compared to the other treatments, while the CNSL-castor oil group exhibited reduced gene expression, except for TNF. The commercial blend of cashew nut liquid and castor oil modulated the inflammatory response against Eimeria spp. In the absence of the parasite, there was no stimulation of genes involved in the inflammatory response, demonstrating that the blend is an effective tool in specifically modulating the immune system of birds afflicted with coccidiosis.