Effect of live Eimeria vaccination or salinomycin on growth and immune status in broiler chickens receiving in-feed inclusion of gelatin and vitamin E.

This experiment determined if 2% of gelatin, to improve the levels of proline and glycine in the diet, and 70 mg/kg of vitamin E supplementation would relieve the impaired performance of male Cobb broilers vaccinated for coccidiosis. Half of the chicks were vaccinated via water (live oocysts), while the other half received medication (salinomycin) in the feed until 35 d of age. The effects of coccidiosis vaccine on performance and mRNA levels of genes involved in mucin synthesis, cytokines, trefoil family factor-2 (TFF2), and metabolic processes (CD36) in the jejunum of broilers were measured. Vaccination negatively affected performance in the first 21 d; however, the inclusion of gelatin and vitamin E reduced this negative response. Additionally, supplementation with these nutrients led to an improvement in broilers receiving the coccidiostat (P < 0.05). From 21 to 35 d, birds treated with gelatin and coccidiosis vaccine experienced better body weight gain than birds without gelatin and vitamin E (P < 0.05). Vaccinated chickens had decreased body weight and decreased anti-inflammatory cytokine expression. Furthermore, they had increased inflammatory cytokine expression, mucin 2 expression, and TFF2 compared to salinomycin-fed broilers (P < 0.05). Transcripts for IL-1B, IFN-y, MUC2, TFF2 were decreased while mRNAs for IL-4 and IL-10 increased in salinomycin-fed broilers compared to vaccinated broilers (P < 0.05). In conclusion, broilers vaccinated against coccidiosis increase their pro-inflammatory immune status and mucin expression compared to broilers receiving salinomycin. These events may contribute to lower performance in vaccinated broiler chicks. Moreover, vitamin E and gelatin can minimize the vaccine's negative immune effects and promote better performance.

Modeling the performance of broilers under heat stress.

A meta-analysis was developed to model performance depression in heat stress (HS), to analyze the influence of HS type (cyclic or constant), and to assess the correlation between dietary electrolyte balance (DEB) and HS in broilers. Two databases (Dat) with performance and temperature were constructed (initial phase - up to 21 d of age - 14 articles, 7,667 animals, average replicate number treatment-ARN/T, 5 and growing phase - over 21 d of age - 74 articles and 25,145 broilers, ARN/T, 7). The criteria for article selection were (1) experiments using at least 2 temperatures (thermoneutral and high temperature); (2) results of ADFI and ADG; (3) feed and water ad libitum during the experiment. Each treatment was classified as cyclic or constant HS and the HS group response was calculated relative to the thermoneutral group. Performance was evaluated as raw data or as relativized information (indicated as "HS effect or ≠"), expressed as a percentage of the difference between results. The models to predict "HS effect" showed that for the initial phase, only ADG was influenced by HS, while for the grower phase, prediction equations were created for ADFI and ADG. Considering the simplest models, there was a reduction of 1.4% in ADFI and 2.1% in ADG for each unit (°C) above the upper critical temperature for broilers older than 21 d. Feed conversion (FC) was not affected by HS in any of the studied phases. Constant HS proved to be more negative than cyclic HS to broiler performance after 21 d of age. The relation between DEB and performance of broilers under HS was analyzed considering broilers over 21 d of age, and very weak correlations were observed. It was concluded that HS affects broilers over 21 d more, although FC is not affected. ADFI is the most important variable affected by HS and the relation between the DEB of the diet and HS is very weak. The empirical models generated in this study accurately predicted ADG and ADFI of broilers exposed to HS and can be used to minimize those effects on poultry production.

Changes in the ceca microbiota of broilers vaccinated for coccidiosis or supplemented with salinomycin.

The objective of this study was to characterize differences in the cecal microbiota of chickens vaccinated for coccidiosis or receiving salinomycin in the diet. In this study, 140 male 1-day-old broiler chickens were divided in 2 groups: vaccine group (live vaccine) vaccinated at the first day and salinomycin group (125 ppm/kg since the first day until 35 d of age). Each treatment was composed for 7 replicates of 10 birds per pen. At 28 d, the cecal content of one bird per replicate was collected for microbiota analysis. The genetic sequencing was conducted by the Miseq Illumina platform. Vaccine group showed lower body weight, weight gain, and poorer feed conversion in the total period (P < 0.05). Bacterial 16S rRNA genes were classified as 3 major phyla (Bacteroidetes, Firmicutes, and Proteobacteria), accounting for more than 98% of the total bacterial community. The microbiota complexity in the cecal was estimated based on the α-diversity indices. The vaccine did not reduce species richness and diversity (P > 0.05). The richness distribution in the salinomycin group was larger and more uniform than the vaccinated birds. Salinomycin group was related to the enrichment of Bacteroidetes, whereas Firmicutes and Proteobacteria phyla were in greater proportions in the vaccine group. The last phylum includes a wide variety of pathogenic bacteria. The vaccine did not decrease the species richness but decreased the percentage of Bacteroidetes, a phylum composed by genera that produce short-chain fatty acids improving intestinal health. Vaccine group also had higher Proteobacteria phylum, which may help explain its poorer performance.

Toward better estimates of the real-time individual amino acid requirements of growing-finishing pigs showing deviations from their typical feeding patterns.

Pigs exposed to stressors might change their daily typical feeding intake pattern. The objective of this study was to develop a method for the early identification of deviations from an individual pig's typical feeding patterns. In addition, a general approach was proposed to model feed intake and real-time individual nutrient requirements for pigs with atypical feeding patterns. First, a dynamic linear model (DLM) was proposed to model the typical daily feed intake (DFI) and daily gain (DG) patterns of pigs. Individual DFI and DG dynamics are described by a univariate DLM in conjunction with Kalman filtering. A standardized tabular cumulative sum (CUMSUM) control chart was applied to the forecast errors generated by DLM to activate an alarm when a pig showed deviations from its typical feeding patterns. The relative feed intake (RFI) during a challenge period was calculated. For that, the forecasted individual pig DFI is expressed as its highest DFI relative to the intake during pre-challenge period. Finally, the DLM and RFI approaches were integrated into the actual precision-feeding model (original model) to estimate real-time individual nutrient requirements for pigs with atypical feeding patterns. This general approach was evaluated with data from two studies (130 pigs, at 35.25 ± 3.9 kg of initial BW) that investigated during 84 days the effect of precision-feeding systems for growing-finishing pigs. The proposed general approach to estimating real-time individual nutrient requirements (updated model) was evaluated by comparing its estimates with those generated by the original model. For 11 individuals out of 130, the DLM did not fit the observed data well in a specific period, resulting in an increase in the sum of standardized forecast errors and in the number of time steps that the model needed to adapt to the new patterns. This poor fit can be identified by the increase in the CUMSUM with a consequent alarm generated. The results of this study show that the updated model made it possible to reduce intra-individual variation for the estimated lysine requirements in comparison with the original model, especially for individuals with atypical feeding patterns. In conclusion, the DLM in conjunction with CUMSUM could be used as a tool for the online monitoring of DFI for growing-finishing pigs. Moreover, the proposed general approach allows the estimation of real-time amino acid requirements and accounts for the reduced feed intake and growth potential of pigs with atypical feeding patterns.

Effects of rice protein coating enriched with essential oils on internal quality and shelf life of eggs during room temperature storage.

The effectiveness of rice protein coatings enriched with essential oils on maintaining interior quality 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, and yolk index (YI) in uncoated eggs (control treatment) and eggs coated with rice protein concentrate at 8% enriched or not with different essential oils (1%): tea tree (Melaleuca alternifolia), copaíba (Copaifera langsdorffii), or thymo (Thymus vulgaris). The HU and YI were higher in coated eggs (P < 0.001). Data were submitted to variance analysis, and the statistical models included the effects of treatments (coating types), storage periods (weeks), and interaction (treatments by storage periods). Weight loss increased (P < 0.001) during long-term storage. Uncoated eggs showed the highest weight loss (5.43%), whereas coatings of rice protein alone (4.23%) or enriched with tea tree (4.10%), copaíba (3.90%), and thymo (4.08%) solutions were effective in preventing weight lost (P < 0.001). The coating use preserved the internal quality of the eggs for up to 3 wk longer than uncoated eggs in terms of HU, YI, and pH. Uncoated eggs had the worst (P < 0.001) HU (58.46), albumen pH (9.48), and YI (0.33) after 6 wk of storage. In conclusion, the use of coatings based on rice protein concentrate enriched with different essential oils influences the internal quality of eggs during storage and may be an effective alternative for increasing the shelf life of commercial eggs.

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.

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.

Assessing the accuracy of measurements obtained by dual-energy X-ray absorptiometry on pig carcasses and primal cuts.

Accuracy, trueness, and precision of dual-energy X-ray absorptiometry (DXA) assessment of pig carcasses and primal cuts dissected tissues were evaluated using available region of interests (ROI) and Total Body and Small Animal software modes. Fat mass, lean mass, and bone mineral content (BMC) DXA values were compared to dissected tissue weights (fat, muscle, and bones). Used ROI influenced (P < 0.05) DXA measurements of BMC, fat mass, and lean mass. Configuration modes influenced (P < 0.05) DXA fat mass in shoulders and bellies, whereas BMC estimates differed (P < 0.05) among configuration modes. Equations predicting dissected composition on the basis of DXA measurements showed high coefficients of determination, particularly for fat and lean masses. DXA is able to accurately evaluate the composition of pig carcasses and primal cuts. From a methodological viewpoint, and considering the variations observed in this study, the method for image acquisition and analysis should be chosen on the basis of the item to be evaluated.

Rice protein coating in extending the shelf-life of conventional eggs.

The effectiveness of rice protein coatings or mineral oil on maintaining interior quality and eggshell breaking strength of fresh eggs was evaluated during storage at 20°C for 8 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 mineral oil or rice protein concentrate at 5, 10, or 15%. 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 (8.28%), whereas mineral oil (0.87%) and rice protein at 5% (5.60%), 10% (5.45%), 15% (5.54%) solutions were effective in preventing weight lost (P < 0.001). The use of the coatings preserved the internal quality of the eggs for up to 4 wk longer than uncoated eggs (HU, YI, and pH). Uncoated eggs had the worst (P < 0.001) HU (54.45), albumen pH (9.18), and YI (0.28) after 8 wk of storage. Among the coated eggs, the mineral oil had the best values of HU (70.54), pH (8.48), and YI (0.35) after storage. The eggs coated with 5, 10, and 15% of rice protein presented results with similar intern quality between them and intermediary quality in relation to the others treatments 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, the use of coatings based on rice protein concentrate or mineral oil influences the internal quality of eggs during storage and may be an effective alternative for increasing the shelf-life of commercial eggs.

Repeatability and reproducibility of measurements obtained by dual-energy X-ray absorptiometry on pig carcasses.

The precision of a dual-energy X-ray absorptiometry (DXA) device in terms of repeatability and reproducibility was evaluated on nine left half-carcasses from pigs with large variability in body weight and fat content. Repeatability was assessed by scanning each carcass 10 times sequentially in the same position. Reproducibility was assessed by scanning each carcass in 10 different positions. Images were analyzed with DXA software using a custom region of interest (ROI) and the standard head, trunk, arm, and leg ROI. Predicted values from the DEXA for bone mineral content (BMC), bone area, bone mineral density (BMD), total weight, soft-tissue weight, fat-tissue weight, and lean-tissue weight were considered. Repeatability was associated with the variance between measurements on the same carcass in the same position (repeatability conditions). An average variance value was obtained with all the carcasses combined, and the SD was calculated as the square root of this combined variance. The CV was the ratio between the SD of the measurements and its average value. Reproducibility was calculated for each carcass as the difference between the variance obtained under the reproducibility conditions and that obtained under the repeatability conditions. The effects of the ROI and conditions were evaluated by ANOVA and Tukey's test. Means of BMC, bone area, BMD, fat tissue, and lean tissue differed among the ROI (P < 0.05) in both the repeatability and reproducibility conditions. The CV of DXA measurements under repeatability condition obtained in the head, arm, and leg ROI was lesser than 1%. Only the repeatability errors of fat tissue differed (P < 0.05) among the ROI, with the lowest precision found for the trunk ROI. The reproducibility errors of BMC, bone area, fat tissue, and lean tissue differed (P < 0.05) among the ROI. The custom ROI had reproducibility errors greater than 2% for fat tissue and greater than 3.5% for BMC and bone area. In addition, the trunk ROI had the highest reproducibility errors for fat tissue (20.7%) and lean tissue (6.2%) when compared to the other ROI. In conclusion, repeatability and reproducibility results obtained for most of the studied ROI indicate that DXA is a valuable tool for carcass evaluation. From a methodological viewpoint and considering the variations observed in this study, the ROI should be chosen based on the item to be evaluated or on the conditions in which the DXA measurements are to be taken.

Newcastle disease vaccination in captive-bred wild birds.

The breeding of wild birds in captivity assumes an increasingly important role in conservation due to the loss of species and their habitats. Providing the environmental and nutritional needs of species kept in captivity is the key for achieving success in such initiatives. Among the flock health practices, we highlight here wild bird vaccination, a scarcely studied subject. This study clinically and serologically evaluates the effect of applying a vaccination protocol against Newcastle disease in three groups of ornamental wild birds. The responses observed in 10 ornamental chickens were compared to those recorded in 12 ring-neck pheasants (Phasianus colchicus), 6 psittacines (2 cockatiels Nymphicus hollandicus, 2 lorikeets Trichoglossus haematodus molucanos, and 2 eastern rosellas Platycercus eximius), and 6 touracos (2 guinea Tauraco persa, 2 white-cheeked Tauraco leucotis, and 2 violet Musophaga violacea). One drop of each live Newcastle HB1 and La Sota vaccines were ocularly instilled on the 1st and 21st experimental days, respectively. On the 112th day, one shot of an inactivated oily Newcastle vaccine was intramuscularly injected. Serum samples were submitted to the Newcastle disease virus antibody Test Kit ELISA-BioChek. Except for the psittacines, other bird species showed a considerable increase in the antibody titers. However, their mean antibody titers differed significantly (P < 0.05) from that recorded in the chickens.

Environmental impacts of precision feeding programs applied in pig production.

This study was undertaken to evaluate the effect that switching from conventional to precision feeding systems during the growing-finishing phase would have on the potential environmental impact of Brazilian pig production. Standard life-cycle assessment procedures were used, with a cradle-to-farm gate boundary. The inputs and outputs of each interface of the life cycle (production of feed ingredients, processing in the feed industry, transportation and animal rearing) were organized in a model. Grain production was independently characterized in the Central-West and South regions of Brazil, whereas the pigs were raised in the South region. Three feeding programs were applied for growing-finishing pigs: conventional phase feeding by group (CON); precision daily feeding by group (PFG) (whole herd fed the same daily adjusted diet); and precision daily feeding by individual (PFI) (diets adjusted daily to match individual nutrient requirements). Raising pigs (1 t pig BW at farm gate) in South Brazil under the CON feeding program using grain cultivated in the same region led to emissions of 1840 kg of CO2-eq, 13.1 kg of PO4-eq and 32.2 kg of SO2-eq. Simulations using grain from the Central-West region showed a greater climate change impact. Compared with the previous scenario, a 17% increase in climate change impact was found when simulating with soybeans produced in Central-West Brazil, whereas a 28% increase was observed when simulating with corn and soybeans from Central-West Brazil. Compared with the CON feeding program, the PFG and PFI programs reduced the potential environmental impact. Applying the PFG program mitigated the potential climate change impact and eutrophication by up to 4%, and acidification impact by up to 3% compared with the CON program. Making a further adjustment by feeding pigs according to their individual nutrient requirements mitigated the potential climate change impact by up to 6% and the potential eutrophication and acidification impact by up to 5% compared with the CON program. The greatest environmental gains associated with the adoption of precision feeding were observed when the diet combined soybeans from Central-West Brazil with corn produced in Southern Brazil. The results clearly show that precision feeding is an effective approach for improving the environmental sustainability of Brazilian pig production.

Meta-analytic study of organic acids as an alternative performance-enhancing feed additive to antibiotics for broiler chickens.

The effect of organic acids as an alternative to antibiotics on the performance of broiler chickens was evaluated by meta-analysis, identifying and quantifying the main factors that influence results. A total of 51,960 broilers from 121 articles published between 1991 and 2016 were used. Interactions of additives [non-supplemented group (control), organic acids, and growth promoter antibiotics] with microbial challenge (with or without inoculation of pathogenic microorganisms) were studied on performance variables. Moreover, the effects of organic acids, used individually or in blends, were evaluated. Relative values of average daily gain (ADG) and average daily feed intake (ADFI) were obtained in relation to control: ΔADG and ΔADFI, respectively. Analysis of variance-covariance revealed lower ADG with organic acids when compared to antibiotics (P < 0.05). There was a significant interaction between the additives and the challenge on feed conversion ratio (FCR) (P < 0.01) and on viability (P < 0.05). Without challenge, organic acids improved broilers' FCR (P < 0.01), presenting results similar to antibiotics (P > 0.05). Under challenge, the organic acids were again effective on FCR (-5.67% in relation to control, P < 0.05), but they did not match antibiotics (-13.40% in relation to control, P < 0.01). Viability was improved only under challenge conditions, and only by antibiotics (+4.39% in relation to control, P < 0.05). ADG (P < 0.05) and FCR (P < 0.01) were increased by blends of organic acids, but not by the organic acids used alone (P > 0.05). ADFI and production factor were not influenced by the treatments (P > 0.05). ΔADFI of organic-acid supplemented group showed a linear influence on ΔADG, which increases 0.64% at every 1% increase in ΔADFI. In conclusion, organic acids can be utilized as performance enhancing, but the results are lower than those found with antibiotics, particularly under microbial challenge. The blends of organic acids provide better results than the utilization of one organic acid alone.

Feeding behavior of growing-finishing pigs reared under precision feeding strategies.

The feeding behavior of growing-finishing pigs reared under precision feeding strategies was studied in 35 barrows and 35 females (average initial BW of 30.4 ± 2.2 kg) over 84 d. Five different feeding programs were evaluated, namely a conventional 3-phase program in which pigs were fed with a constant blend of diet A (high nutrient density) and diet B (low nutrient density) and 4 daily phase-feeding programs in which pigs were fed daily with a blend meeting 110, 100, 90, or 80% of the individual Lys requirements. Electronic feeder systems automatically recorded the visits to the feeder, the time of the meals, and the amount of feed consumed per meal. The trial lasted 84 d and the database contained 59,701 feeder visits. The recorded database was used to calculate the number of meals per day, feeding time per meal (min), intervals between meals (min), feed intake per meal (g), and feed consumption rate (feed intake divided by feeding time per meal, expressed in g/min) of each animal. The feeding pattern was predominantly diurnal (73% of the feeder visits). Number of meals, duration of meals, time between meals, feed consumed per meal, and feed consumption rate were not affected by the feeding programs. The females ingested 19% less feed per meal and had a 6% lower feed consumption rate in comparison with the barrows ( < 0.05). Pig feeding behavior was not correlated with diet composition. However, feed efficiency was negatively correlated with amount of feed consumed per meal ( = -0.38, < 0.05) and feed consumption rate ( = -0.44, < 0.05). Feed consumption rate was also negatively correlated with protein efficiency ( = -0.44, < 0.05). Multivariate analysis indicated that feed consumption rate and number of meals per day are the variables related most closely to pig production performance results. Current results indicate that using precision feeding as an approach to reduce Lys intake does not interfere with the feeding behavior of growing-finishing pigs.

Precision feeding can significantly reduce lysine intake and nitrogen excretion without compromising the performance of growing pigs.

This study was developed to assess the impact on performance, nutrient balance, serum parameters and feeding costs resulting from the switching of conventional to precision-feeding programs for growing-finishing pigs. A total of 70 pigs (30.4±2.2 kg BW) were used in a performance trial (84 days). The five treatments used in this experiment were a three-phase group-feeding program (control) obtained with fixed blending proportions of feeds A (high nutrient density) and B (low nutrient density); against four individual daily-phase feeding programs in which the blending proportions of feeds A and B were updated daily to meet 110%, 100%, 90% or 80% of the lysine requirements estimated using a mathematical model. Feed intake was recorded automatically by a computerized device in the feeders, and the pigs were weighed weekly during the project. Body composition traits were estimated by scanning with an ultrasound device and densitometer every 28 days. Nitrogen and phosphorus excretions were calculated by the difference between retention (obtained from densitometer measurements) and intake. Feeding costs were assessed using 2013 ingredient cost data. Feed intake, feed efficiency, back fat thickness, body fat mass and serum contents of total protein and phosphorus were similar among treatments. Feeding pigs in a daily-basis program providing 110%, 100% or 90% of the estimated individual lysine requirements also did not influence BW, body protein mass, weight gain and nitrogen retention in comparison with the animals in the group-feeding program. However, feeding pigs individually with diets tailored to match 100% of nutrient requirements made it possible to reduce (P<0.05) digestible lysine intake by 26%, estimated nitrogen excretion by 30% and feeding costs by US$7.60/pig (-10%) relative to group feeding. Precision feeding is an effective approach to make pig production more sustainable without compromising growth performance.

The impact of feeding growing-finishing pigs with daily tailored diets using precision feeding techniques on animal performance, nutrient utilization, and body and carcass composition.

The impact of moving from conventional to precision feeding systems in growing-finishing pig operations on animal performance, nutrient utilization, and body and carcass composition was studied. Fifteen animals per treatment for a total of 60 pigs of 41.2 (SE = 0.5) kg of BW were used in a performance trial (84 d) with 4 treatments: a 3-phase (3P) feeding program obtained by blending fixed proportions of feeds A (high nutrient density) and B (low nutrient density); a 3-phase commercial (COM) feeding program; and 2 daily-phase feeding programs in which the blended proportions of feeds A and B were adjusted daily to meet the estimated nutritional requirements of the group (multiphase-group feeding, MPG) or of each pig individually (multiphase-individual feeding, MPI). Daily feed intake was recorded each day and pigs were weighed weekly during the trial. Body composition was assessed at the beginning of the trial and every 28 d by dual-energy X-ray densitometry. Nitrogen and phosphorus excretion was estimated as the difference between retention and intake. Organ, carcass, and primal cut measurements were taken after slaughter. The COM feeding program reduced (P < 0.05) ADFI and improved G:F rate in relation to other treatments. The MPG and MPI programs showed values for ADFI, ADG, G:F, final BW, and nitrogen and phosphorus retention that were similar to those obtained for the 3P feeding program. However, compared with the 3P treatment, the MPI feeding program reduced the standardized ileal digestible lysine intake by 27%, the estimated nitrogen excretion by 22%, and the estimated phosphorus excretion by 27% (P < 0.05). Organs, carcass, and primal cut weights did not differ among treatments. Feeding growing-finishing pigs with daily tailored diets using precision feeding techniques is an effective approach to reduce nutrient excretion without compromising pig performance or carcass composition.

A meta-analysis of the feed intake and growth performance of broiler chickens challenged by bacteria.

The aim of this meta-analysis was to determine the effect of a bacterial immune challenge (Clostridium spp., Escherichia coli, and Salmonella spp.) on the ADFI, ADG, and nutrient partitioning (maintenance requirements and feed efficiency) of broiler chickens. The database used for the meta-analysis included 65 articles that were published between 1997 and 2012 concerning a total of 86,300 broilers and containing information on the feed intake, protein intake, methionine intake, and weight gain of broilers that were challenged with Clostridium spp., E. coli, or Salmonella spp. and were fed or not fed feed additives. The results of the ADFI and the ADG of the challenged broilers were transformed into values relative to those obtained in control broilers (ADG and ADFI). The meta-analysis involved 3 sequential analyses: graphical, correlation, and variance-covariance analysis. The results obtained for the birds that were challenged with Clostridium spp., E. coli, or Salmonella spp. indicated that the ADFI was reduced by 16, 7, and 9%, respectively, and the ADG was reduced by 40, 10, and 29%, respectively. When the results for the challenged birds that were treated or nontreated were compared, ADFI reductions of 26.0 and 26.5% and ADG reductions of 2.9 and 21.6% were observed, respectively. Regression analyses of the ADG as a function of the protein or methionine intake of the challenged birds suggested that nutrients were diverted to the immune system. The relationship between the ADG and the ADFI was quadratic in the challenged and nontreated or treated broilers, as well as for each disease. The intercept of the regression-based curves for the data from all of the challenges were different from zero and negative (-2.20, -0.70, and -3.37, respectively), indicating that all of the challenges increased the maintenance requirements. In general, this meta-analysis allowed for the quantification of the effects of bacteriological challenges on the maintenance and feed efficiency of broiler chickens, and the knowledge that was generated in this study is applicable to broiler nutrition and for modeling their nutritional requirements.