Floor Pens Research Articles

BCAA interactions: how do they influence broiler performance, intestinal morphometry, lipid profile, and liver health?

ABSTRACT An experiment was conducted to assess the effects of the BCAA and their interactions on performance, carcass composition, lipid metabolism, liver health, and intestinal morphometry in broiler chickens. Male chickens (n = 1080) were randomly assigned into floor pens in a 3 × 3 factorial design with 3 dietary ratios of SID Leu:Lys (110, 150, and 190%), and 3 dietary ratios of SID Ile-Val:Lys (68–77, 78–87, and 88–97%). Performance parameters were assessed from 1 to 35 days of age. Additionally, blood parameters, carcass composition through DEXA analysis, and intestinal morphometry of the small intestine were evaluated in birds at 35 days of age. Data were subjected to ANOVA and the Tukey Test was used to determine differences between treatments (p ≤ 0.05). Feed intake, feed conversion ratio, and body fat of birds were reduced when SID Ile-Val:Lys increased from 68–77 to 88–97% (p < 0.05). Serum glucose, total cholesterol, and triglycerides were influenced by BCAA interactions (p < 0.05). Alkaline phosphatase and gamma-glutamyl transferase levels were reduced when SID Leu:Lys ratio increased from 110 to 190% (p < 0.05). However, the alanine aminotransferase levels increased when both SID Leu:Lys and SID Ile-Val:Lys increased from 110 to 190%, and 68–77 to 88–97%, respectively (p < 0.05). The highest SID Leu:Lys ratio of 190% resulted in the highest villus height-to-crypt depth ratio in all three portions of the intestine, whereas the highest SID Ile-Val:Lys ratio of 88–97% resulted in the highest ratio only in the jejunum and ileum (p < 0.05). In conclusion, the results of this study provide valuable insights into the inclusion of BCAA in broiler diets and their effects on performance, body fat content, intestinal morphometry, lipid metabolism, and liver health.

Effects of sodium bisulfate or sodium sesquicarbonate as a sodium source in broiler chicken diets with or without a coccidiosis challenge.

Broilers commonly experience stressors such as coccidiosis, a parasitic infection that results in intestinal damage, malabsorption, and performance losses. The poultry industry is exploring alternatives to anticoccidials for controlling coccidiosis, especially through the enhancement of gut health. Sodium bisulfate (NaHSO4; SBS), an acid salt, has been used for many years as a litter acidifier to reduce aerial ammonia in poultry housing. More recently, SBS has shown promise as a feed additive that improves growth performance through enhancing gut health in poultry. Two trials of 1,920 broiler chicks each were raised to 42 d in floor pens. Chicks were randomly divided into 1 of 4 treatments (480 chicks/treatment) on d 0 that utilized SBS (0.3 or 0.4% of diet) or control diets using sodium sesquicarbonate (0.2 or 0.3% of diet) as a sodium source. In Trial 2, birds were challenged with a 2 × dose of coccidiosis vaccine on d 0. Growth performance was measured on d 0, 14, 28, and 42. Each trial was analyzed independently to yield results for non-challenged or coccidiosis-challenged conditions. All data were analyzed with means separation using a Duncan's test. SBS and control treatments with equivalent sodium contributions were also directly compared. Significance was accepted at P ≤ 0.05. On d 28, broilers fed 0.4% SBS weighed more (P < 0.05) than broilers from either control, regardless of challenge status. This effect was sustained in the challenged broilers at d 42 but was not different (P > 0.05) in non-challenged broilers. No differences (P > 0.05) in feed intake or mortality were observed in either trial. Birds fed 0.4% SBS had lower feed conversion than both control treatments for d 0-42, regardless of challenge status. Collectively, these results indicate that SBS promoted growth performance with and without a coccidiosis challenge more than that of sodium sesquicarbonate as a supplemental sodium source. Because experimental treatments were balanced for mineral content, it is possible the sulfate content of SBS influenced these results.

Effects of graded yeast cell wall supplementation on growth performance, immunity and intestinal development of broiler chickens raised in floor pens for 42 days.

This study was conducted to evaluate the effects of dietary supplementation of a novel soluble yeast cell wall (YCW) on growth performance, gut health, intestinal morphology, and immune response in broiler chickens for 42 days. A total of 480 one-day-old Cobb 500 male broilers were randomly assigned to four treatments with six replicates and each replicate of twenty broiler chickens: a control group (CON) without feed additive supplementation, and three groups supplemented with YCW at 0.025 % (YCW1), 0.050 % (YCW2), and 0.100 % (YCW3). Results showed that 0.025 % and 0.100 % YCW supplementation significantly increased (P < 0.05) final body weight (BW) and overall body weight gain (BWG) while reducing overall feed conversion ratio (FCR) compared to the CON group. The YCW supplementation also improved (P < 0.05) the balance of gut microbiota by increasing beneficial bacteria (Lactobacillus) and decreasing Salmonella, a potential foodborne pathogen in humans in the ceca. Although intestinal morphology was not significantly affected, YCW supplementation numerically increased the villus height: crypt depth ratio (VH:CD) compared to the CON group. Furthermore, YCW reduced the mRNA expression of pro-inflammatory cytokines (IL-1β and INF-γ) and tight junction protein claudin-1 (CLDN-1) (P < 0.05), suggesting balanced immune response and improved intestinal barrier function. In conclusion, the supplementation of soluble YCW in broiler diets positively influenced growth performance, gut microbiota composition, and immune response, demonstrating its potential as a viable alternative to antibiotics for improving broilers' health.

A dual strain probiotic administered via the waterline beneficially modulates the ileal and cecal microbiome, sIgA and acute phase protein levels, and growth performance of broilers during a dysbacteriosis challenge

Intestinal dysbacteriosis is increasing in broilers due to the reduced use of antibiotics in feed. This study tested the effect of daily waterline administration of a dual-strain probiotic comprising Lactobacillus acidophilus AG01 and Bifidobacterium animalis subspecies lactis AG02, on growth performance and intestinal health during a 3-step microbial challenge. In total, 900 Ross 308 males were assigned to 36 floor pens (25 birds/pen, 12 pens/treatment) in a completely randomized design. Birds were fed a corn, wheat and soybean-meal based diet. Diets were formulated in 3 phases (starter: 1 to 10; grower: 11 to 24; finisher: 25 to 42 d of age). Treatments comprised a non-challenged control (NC), challenged control (CC), and the CC supplemented with 1 × 108 colony forming units (CFU)/bird/day of the probiotic (CC+Probiotic). The challenge comprised 1 × 108 CFU/bird of Avian Pathogenic Escherichia coli on d 7, 4,000 oocysts/bird of Eimeria on d 15 and 1 × 109 CFU/bird of C. perfringens on d 18, 19 and 20. Growth performance was monitored over 42 d, blood samples, and digesta were collected and intestinal dysbacteriosis scoring was performed. Compared to NC birds, CC birds exhibited reduced BW (all phases), reduced feed intake (starter and grower phase), increased FCR (grower phase and overall; P < 0.05), reduced ileal lactic acid bacteria concentrations (d 24 and 42), and increased cecal E. coli (d 24; P < 0.05). Compared to CC birds, CC+Probiotic birds exhibited increased BW, BW gain and feed intake during grower phase (P < 0.05), increased ileal lactic acid bacteria at d 24 and 42 and reduced ileal C. perfringens at d 24, increased mucosal secretory IgA and reduced serum alpha-1-acid-glycoprotein at d 42. The overall growth performance of CC+Probiotic birds was equivalent to NC birds. These results confirm the efficacy of the dual strain probiotic for mitigating the negative effects of a multi-microbial challenge, improving gut health and growth performance in commercial broilers under dysbacteriosis challenge.

Influence of diet nutrient density and a multicarbohydrase containing α-galactosidase on performance, carcass characteristics, breast myopathies, and nutrient utilization of broilers reared from 1 to 42 days of age

This study evaluated the effects of nutrient density and the usage of a multicarbohydrase containing α-galactosidase enzyme (CAG) on broiler performance, carcass characteristics, and nutrient utilization from 1 to 42 d of age. A total of 1,800 d-old YPM x Ross 708 male broilers were distributed randomly into 72 floor pens (25 birds/pen) and assigned to 1 of 6 treatments (12 replicates/treatment). Three basal diets were formulated with 2 ME levels (adequate (AE) and 100 kcal/kg reduced (RE)) and 2 amino acid (AA) densities (96 and 90%) following Ross 708 nutrient specifications. The first diet, AE96AA, contained AE and 96% AA density. The second diet, RE96AA, contained RE with 96% AA density. The third diet, RE90AA, contained RE with 90% AA density. Additional treatments were prepared by supplementing 0.2 g CAG per kg feed to the basal diets. Broiler performance (d 14, 28, and 42), processing yields (d 43), breast myopathies (d 43), apparent ileal nutrient digestibility (d 42), and digestible nutrient intake (d 29 to 42) were determined. Data were analyzed as a 3 × 2 (nutrient density x CAG) factorial arrangement of treatments. Nutrient density x CAG interactions were observed for multiple measurements including feed conversion ratio (FCR; d 1 to 42), CP digestibility, and apparent ileal digestible energy (AIDE). Day 1 to 42 FCR was reduced when broilers were fed RE90AA with CAG compared to RE90AA without CAG (P ≤ 0.05). Crude protein digestibility increased when broilers consumed AE96AA without CAG compared to RE90AA, whereas CAG inclusion allowed for similar CP digestibility between all nutrient densities (P ≤ 0.05). Without CAG inclusion, AIDE had a stepwise decrease from AE96AA to RE90AA, while CAG supplemented AE96AA and RE90AA had similar AIDE (P ≤ 0.05). Inclusion of CAG decreased FCR, and increased nutrient digestibility of broilers fed nutrient-reduced diets.

Early behavioral indicators of aberrant feces in newly-weaned piglets.

Post-weaning diarrhea (PWD) is a frequently occurring health and welfare issue in weaned piglets. Behavioral changes indicating impaired health may be detectable before the onset of signs and could be useful to detect the development of PWD early, enabling targeted and timely interventions. Current algorithms enable automated behavioral classification on the group level, while PWD may not affect all piglets in one pen and individual level analysis may be required. Therefore, this study aimed to assess whether changes in pen activity or individual piglet behavior can be early indicators of the occurrence of PWD. During 3 replicated rounds, 72 piglets (Sus scrofa domestica, Landrace x Large White) weaned at 27days of age, were housed in 4 pens with 6 piglets each. Individual fecal color and consistency were scored (0-5; ≥ 3 considered as aberrant feces) six times during the first two weeks post-weaning using rectal swabs. Additionally, using a similar scoring scale, feces on the pen floor were assessed daily. Two methods were applied for behavioral scoring. Individual behaviors (eating, drinking, standing, walking; n = 48) were scored manually and instantaneously with a five-minute interval from videos of the first two rounds, while pen activity (eating, drinking, moving; n = 12) was analyzed automatically and continuously using a commercially available algorithm from videos of all three rounds. Piglets showing a relatively higher proportion of standing behavior one day before fecal scoring had increased odds of an aberrant fecal color score (odds ratio (OR): 4.8; 95% confidence interval (CI): 1.5-15.3). Furthermore, odds of aberrant colored feces increased in pens where piglets showed more moving activity two days before (OR: 6.14; 1.26 < 95%CI < 29.84), which was also found for fecal consistency (OR: 4.77; 95%CI: 1.1-21.6). Our results indicate that increased standing in individual piglets and an increased moving activity on the pen level may be important behavioral indicators of PWD before the onset of diarrhea. Further development of current algorithms that can identify behavioral abnormalities in groups, from the pen to the individual level, may therefore be a promising avenue for improved and targeted health and welfare monitoring.

Effect of dietary β-mannanase supplementation on growth performance and nutrient retention in broiler chickens fed corn-soybean meal-based diets with low energy and amino acid density

The present study was conducted to evaluate the effect of two different β-mannanases on growth performance and nutrient retention of broiler chickens fed a diet with low energy and amino acid density. A total of 312 one-day-old male broiler chickens (Ross 308) were placed in floor pens and fed a standard starter diet for 16 days. They were then randomly moved to stainless steel cages and distributed into three groups, with 13 replicates of 8 chickens each. The control group received a corn-soybean meal-based grower diet with reduced metabolizable energy by ∼100 kcal/kg and a 10-12% reduction of digestible amino acids (lysine, methionine, and threonine). Titanium oxide was added at 0.5% of diet as an indigestible marker. The other groups were fed the same diet supplemented with either β-mannanase A derived from Thermothelomyces thermophilus (100 g β-mannanase/MT grower diet) or β-mannanase B derived from Paenibacillus lentus (350 g β-mannanase/MT grower diet). The trial lasted for 7 days from d 17 to d 23, comprising 4 days of acclimatization followed by 3 days of sample collection. Final body weight (d 23), body weight gain (d 17-23), and feed intake (d 17-23) of broiler chickens did not differ among the groups. However, both β-mannanases significantly improved the feed conversion ratio during d 17-23 (P = 0.039) and nitrogen retention (P = 0.028) in broiler chickens compared to the control group. Moreover, dietary supplementation with β-mannanase A significantly increased dry matter retention (P = 0.050), organic matter retention (P = 0.028), and nitrogen-corrected apparent metabolizable energy (AMEn; P = 0.033) compared to the control group. In conclusion, supplemental β-mannanase, regardless of the product, improved the growth performance of broiler chickens by improving nutrient retention and dietary AMEn.

Effects of Eimeria challenge on growth performance, intestine integrity, and cecal microbial diversity and composition of yellow broilers

The invasion of Eimeria causes damage to the intestinal barrier, nutrient leakage, and microbial imbalance in poultry. We aimed to investigate the effects of Eimeria infection on growth performance, intestinal integrity, and cecal microbial diversity and composition of yellow broilers. A total of 180 male yellow broilers were randomly divided into an unchallenged control and an Eimeria challenge treatment group within 18 floor pens (10 chicks/pen, 9 replicate pens/group). On day 10, 90 chicks received a cocktail of E. maxima, E. acervulina, and E. tenella oocysts (105/chick) to induce coccidial infection, and the other 90 received an aliquot of PBS. The Eimeria challenge resulted in increased bird feed consumption and FCR from day 11 to 21 (all P < 0.01). Higher fecal Eimeria counts, duodenal, jejunal, and cecal lesions were observed in the challenge group on day 12, 15, 15, 18 respectively (all P < 0.05). Furthermore, the infected birds had larger livers and small intestines, deeper villus crypt, and decreased expression of Claudin-1 on day 21 (all P < 0.05). The 16S rRNA sequencing indicated that alpha diversity (Sobs, Shannon, Simpson, Ace, or Chao) of cecal microbials was not affected by Eimeria challenge (all P > 0.05). However, the PCoA and LEfSe analyses indicated that the Eimeria challenge altered microbial distribution by decreasing the abundance of Firmicutes and enriching the abundance of Proteobacteria at the phylum level. At the genus level, Clostridia vadin BB60 and Lachnospiraceae NK4A136 group were reduced, while Escherichia-Shigella were enriched in the challenged yellow broilers (all P < 0.05). Correlation analyses demonstrated that the birds with higher Lachonospiraceae NK4A136 group and Clostridia vadin BB60, and lower Escherichia-Shigella in their cecal content gained more BW and reached a lower FCR from day 11 to 21 (all P < 0.05). In conclusion, Eimeria infection compromised feed efficiency of yellow broilers by damaging intestinal barrier and shifting cecal microbiota towards colonizers associated with poor performance. Restoring the dysbiotic microbiome could be a potential strategy for improving feed efficiency in yellow broilers under coccidial challenge.

Balancing act: Studying the effect of perch space allowance on welfare in Canadian laying strain pullets raised in floor pens with access to a single-tier perch system to 18 wk of age

The rearing environment for pullets should mirror their later production environment as closely as possible. However, existing perch space recommendations are based on data for laying hens rather than pullets. This study explores the impact of perch space allowances on the welfare of Canadian laying strain pullets raised to 18 wk. Two trials were conducted with 1,032 Lohmann Brown-Lite (LB) and LSL-Lite (LW) pullets each. A randomized complete block (trial) design was used with a 4 (perch space) × 2 (strain) factorial arrangement. Birds were raised in 16 floor pens (3 × 3 m each; 897.67 cm2 per bird). Wooden perches were provided from d 1, allowing 6, 9, 12, or 15 cm perch space per pullet. Data were tested for normality, and log+1 transformed if necessary. Significance was declared at P≤0.05. Data were collected for basic health and functioning (body weight, mortality, pullet width, keel bone damage, and tibia bone parameters), affective states (comb damage, heterophil-to-lymphocyte (H/L) ratios, and behavior), and natural living (perch usage and jumping success). Perch space did not affect mortality, keel bone damage, tibia breaking strength, comb damage, or H/L ratios. At 16 and 18 wk, LB body weight slightly increased while the LW body weight decreased with increasing perch space (P=0.05 and 0.02). At 3 wk, pullets spent a higher percentage of time wing flapping on the perch when provided 15 cm compared to 6 cm (P=0.04). During the scotoperiod at 18 wk, a higher percentage of birds perched with 12 and 15 cm perch space than 6 cm (P<0.01). Pullet width at 18 wk was 12.52 cm (sitting) and 11.66 cm (standing) for the LB and 13.85 cm (sitting) and 12.94 cm (standing) for the LW. Overall, perch space allowance had minor effects on the measured welfare indicators. Based on pullet width, a minimum of 12.5 cm for LW and 13.9 cm for LB pullets should be provided to allow all pullets to sit on the perch simultaneously.

Effects of three different strains of Bacillus-based probiotics and Saccharomyces cerevisiae-based prebiotic on performance, egg components and gene expression of laying hens during phase II of production

This study aimed to investigate the impacts of three strains of probiotics (Bacillus spp. (B.)) and one prebiotic based on Saccharomyces cerevisiae cell wall (SCCW) supplements on performance, egg quality and immune-related gene expression of laying hens. The experiment lasted 16 weeks (52–68 weeks), during which 450 Hisex white layers at 52 weeks were randomly allocated into five dietary regimens (five replications of 18 birds per floor pen): T1, basal diet; T2, basal + 0.5 g/kg B. subtilis (DSM17299); T3, basal + 0.5 g/kg B. subtilis (DSM 5750) and B. licheniformis (DSM 5749); T4, basal + 0.4 g/kg B. subtilis PB6; and T5, basal + 0.25 g/kg SCCW. The results showed that hen-day egg production (HDEP) improved in T4 and T5, egg mass (EM) improved in T3, T4 and T5, and feed conversion ratio (FCR) improved in T4 and T5 compared to T1 (p < .001). Relative wet and dry yolk weight were higher in hens received T2, T4 and T5 (p < .05) and T2, T3, T4 and T5 (p < .001), respectively, compared to T1. Moreover, T2, T4 and T5 had higher expression of GnRH-2 gene compared to T1 (p < .01). In conclusion, the dietary inclusion of SCCW-based prebiotic (T5) and Bacillus spp. probiotic strains, especially T4 B. subtilis PB6 improved production performance, egg components and GnRH-II gene expression of laying hens during phase II of the production cycle and hold a great promise for boosting productivity and supporting health status of layers raised on AGPs-free diets.

Attenuating susceptibility to ascites in cold-stressed broiler chickens fed canola meal-based diets by supplementing arginine or guanidinoacetic acid, either alone or in combination with phenylalanine.

The purpose of this study was to determine the effects of dietary supplementation of arginine (ARG) or guanidinoacetic acid (GAA), with or without phenylalanine (PHE), on the ascites susceptibility in the cold-stressed broilers fed canola meal (CM)-based diet. A total of 450 one-day-old male broiler chicks were randomly allocated to 30 floor pens with 6 replications for each of the 5 treatments. The dietary treatments were as follows: CM-based diet (control), CM-based diet+2.57g/kg ARG, CM-based diet+1.8g/kg GAA, CM-based diet+2.57g/kg ARG+1.5g/kg PHE and CM-based diet+1.8g/kg GAA+1.5g/kg PHE. The groups experienced cold stress induction starting at 32°C on day one, with gradual reductions to 15°C on days 21. The temperature was then held at 15°C for the remainder of the experiment. The supplements ARG+PHE and GAA+PHE resulted in improved feed conversion ratios (FCR) when compared to the control group. In comparison with the control group, supplementation of ARG and ARG+PHE decreased the ascites mortality by increasing the plasma nitric oxide level (NO), blood O2 partial pressure, blood O2 saturation (SO2), and decreasing the blood CO2 partial pressure (PCO2) and right ventricle to total ventricle (RV:TV) ratio. Supplementation of GAA and GAA+PHE also declined ascites mortality by reducing blood PCO2 while increasing blood SO2 and plasma NO levels. Although plasma corticosterone level and RV:TV ratio were similar between the GAA and control groups, adding GAA+PHE significantly reduced both compared to the control group. In summary, supplementing cold-stressed broiler chicken diets with 2.57g/kg ARG may alleviate hypertension. Additionally, 1.8g/kg GAA proves to be an effective substitute for dietary ARG in low-ARG diets, alleviating adverse effects from cold stress. Proper PHE formulation, at 1.5g/kg in this study, is crucial when using ARG and GAA supplements.

Assessing the Effects of Phytogenic Feed Additives on Broilers during a Necrotic Enteritis Challenge

Subclinical necrotic enteritis (NE) is an enteric disease that inflicts significant economic losses in the poultry industry, primarily by reducing performance in commercial flocks but without significant mortality. This study evaluated the effects of a variety of phytogenic blends on broilers’ performance and carcass composition during an induced NE challenge. In this study, 1120 day (d)-old male broilers were allocated to four treatments groups (14 replicate floor pens, 20 birds/pen): the control (CONT) group, fed a basal corn-soybean diet, and three phytogenic blend dietary additives (PHYTO1, PHYTO2, and PHYTO3) added to the basal diet at 150, 250, and 500 mg/kg feed, respectively. Subclinical NE was induced by spraying a concentrated coccidiosis vaccine onto the feed and litter 24 h post-placement. On day 8, two birds/pen were necropsied for NE lesions. On days 8, 14, 28, and 42, the average daily gain (ADG), feed intake (ADFI), and feed conversion ratio (FCR) were calculated. On day 42, two birds/pen were euthanized to assess carcass composition using dual-energy X-ray absorptiometry (DXA). Statistical analyses for all data were performed using the ANOVA procedure (JMP, Pro 16) and significance (p ≤ 0.05) between treatments was determined by the LSD test. There was no effect of treatment on NE lesions. PHYTO1, PHYTO2, and PHYTO3 significantly improved FCR from days 9 to 14, 0 to 14, and 0 to 42 and resulted in greater ADG from days 9 to 14, 29 to 42 and cumulatively on days 0 to 42. Carcass composition data revealed a numerically higher lean-to-fat ratio in the PHYTO groups compared to the CONT group. These results indicate that the dietary supplementation of phytogenic blends could alleviate the adverse effects of NE challenge on broilers’ performance and carcass composition.

Spatiotemporal understanding of behaviors of laying hens using wearable inertial sensors

Automatic detection of behaviors and locations has been increasingly needed in the management of non-cage systems where hen behaviors are highly diverse and active. Here we show a technology to spatiotemporally understand behaviors using a wearable inertial sensor, containing a three-axis accelerometer and three-axis angular velocity sensor (i.e., gyroscope), and a marker. Using supervised machine learning, we first developed a tool that automatically classified and counted 11 behaviors, including comfort behaviors such as head scratching and tail-wagging with small movements as well as dust-bathing with dynamic movements. As expected, these behaviors were observed more frequently in floor pens than in conventional cages (all P < 0.01). We also spatially mapped the behaviors in floor pens and visualized the behavioral frequency in each resource by detecting the colored markers on the sensor. Furthermore, using the time-series information included in the sensor data, we analyzed the behavioral transition from one behavior to another. The behavioral transitions were more complex in floor pens, and the number was higher in body shaking, tail-wagging, resting, litter scratching, dust-bathing, preening, and moving in floor pens than in conventional cages (all P < 0.05). Our tools presented deeper insights into where and what hens behaved and also suggested that connectivity between behaviors, as well as observing the frequency of a behavior, can be an important indicator for welfare assessment in laying hens.

Response of YPM x Ross 708 male broilers to diets containing varying inclusions of phytase, calcium butyrate, and bacitracin methylene disalicylate from 1 to 42 d of age–part 1: performance, processing yields, and nutrient digestibility

This 42-d study evaluated the effects of phytase, calcium butyrate (CB), and bacitracin methylene disalicylate 50 (BMD) on broiler performance, processing yields, and nutrient digestibility. Ross YPM x 708 male broilers (2,880 total) were distributed in 72 floor pens and assigned to 1 of 9 treatments (8 replicates/treatment) on d of hatch. This experiment was a 2 × 4 + 1 factorial arrangement, including 2 phytase concentrations (500 or 1,500 FTU/kg), 4 microbiota modulating feed additive groups (MMFA; none, CB (0.5 g/kg of diet), BMD (55 mg/kg of diet), or both CB and BMD), and a negative control without feed additives. Broiler performance (d 14, 28, and 42), apparent ileal nutrient digestibility (d 28 and 42), and processing yields (d 43) were determined. Day 14 BW increased with BMD inclusion compared to CB and no MMFA in the 1,500 FTU/kg group but BW were similar between all MMFA combined with 500 FTU/kg (P ≤ 0.05). Supplementing BMD increased d 28 BW and reduced d 1 to 28 feed conversion ratio compared to CB and no MMFA (main effect, P ≤ 0.05). Day 42 BW varied depending on dietary phytase concentrations. When diets contained 500 FTU/kg, broilers fed both CB and BMD had a higher BW than broilers fed only CB. Whereas when the inclusion of phytase was increased to 1,500 FTU/kg, broilers fed diets with only BMD or both CB and BMD had higher BW than broilers fed diets with no MMFA (P ≤ 0.05). Phytase concentrations at 1,500 FTU/kg increased (P ≤ 0.05) digestibility of fat (main effect, d 42), phosphorus (d 28 and 42), and apparent ileal digestible energy (main effect, d 42) compared to 500 FTU/kg. In this study, dietary BMD improved broiler growth compared to CB and no MMFA. However, these observed differences between CB and BMD were dependent on dietary phytase concentrations.

Effects of different feeding strategies on behavior and performance in broiler breeder pullets

This study examined the effects of different feeding strategies (diluted diets and feeding frequency) on the behavior and performance of broiler breeder pullets. A total of 3,200 1-day-old female pullets (Ross 308) were randomly distributed over 16 floor pens in 4 rooms and allocated to 1 of 4 treatments: (1) control diet once a day (CON), (2) 20% diluted diet once a day (20-ON), (3) 20% diluted diet twice a day (20-TW), and (4) 30% diluted diet twice a day (30-TW). All the pullets of the different treatments were fed to the same body weight (BW) profile. The 30-TW pullets had the highest and the CON pullets the lowest feed intake, with the 20-ON and 20-TW pullets showing intermediate values. Total water intake was the highest for the 30-TW pullets, followed by the 20-TW and 20-ON pullets, and was the lowest for the CON pullets (P < 0.001). The pullets fed twice a day had the highest total water-to-feed ratio, and the pullets fed once a day had the lowest ratio (P = 0.003). Feeding pullets twice a day yielded the highest average BW uniformity, while the pullets fed once a day had the lowest BW uniformity (P = 0.003). Total mortality was lower in the 20-TW and 30-TW pullets than in the 20-ON pullets, which was primarily caused by fewer dead and graded pullets. The pullets fed twice a day showed overall more eating, more drinking and less sitting, object pecking, and aggressive pecking. The behavior pattern during the daylight period was different for the pullets fed twice a day. Pullets on the diluted feeding strategies were less eager to approach the novel feeder and ate less feed (P = 0.002). In conclusion, feeding pullets with adjusted feeding strategies (feeding twice a day and up to 30% diluted diets) resulted in improved behavior and welfare expressed in decreased stereotypic pecking behavior, and lower eagerness to approach the novel feeder with lower feed intake, with improved BW uniformity and decreased mortality.

PSIV-14 Short-term heat stress affects the plasma metabolome of Florida Cracker sheep

Abstract Florida Cracker sheep is a heritage sheep breed and an endangered species that was developed under natural selection in Florida, US. The objective of this study was to evaluate the effect of short-term heat stress on the plasma metabolome of Florida Cracker ewes (2 yr). A total of fourteen ewes were allocated to heat stress (HT, n = 7) or cooling (CTL, n = 7) conditions for 6 wk during the summer season. Treatment groups were grouped in covered concrete floor pens with similar dimensions and characteristics and had access to shelter, feed, and freshwater ad libitum. The HT pen was exposed to regular ambient temperatures, and for the cooling pen, an evaporative cooling fan was used. Data for ambient temperature and relative humidity of HT and CTL pens were recorded every week to estimate the temperature humidity index (THI). Blood samples were collected from each experimental ewe 1 wk before the start of the experiment (baseline) and at wk 1, 2, 3, 4, 5, and 6 post-treatment. Plasma was extracted from the blood and processed for targeted metabolomics. Targeted metabolomics was performed using Nuclear Magnetic Resonance spectroscopy to quantify a total of 50 metabolites, including organic acids, amino acids, hexoses, lipids, and carnitines. Statistical analysis for biomarker and pathway enrichment was performed using Metaboanalyst 5.0. The THI values for the HT and THI groups ranged from 81.3 to 89.5 and from 73.5 to 75.6, respectively. A total of 19 differentially abundant metabolites were identified between HT and CTL. The pathway enrichment analysis showed upregulation of fatty acid and primary bile biosynthesis, and glutathione, porphyrin, glycine, serine, and threonine metabolism (P ≤ 0.05) in HT compared with CTL sheep. These metabolic pathways could have a role in the response of the ewes to short-term HT. Our findings highlight that short-term HT alters the plasma metabolome of Florida Cracker ewes. Understanding these changes can contribute to the development of effective management strategies to mitigate the detrimental impact of HT on sheep operations in the Southern US.

PSIII-14 Cotton gin byproduct in growing diets for beef steers

Abstract The purpose of this study was to evaluate the performance of beef cattle during the stocker phase when fed different concentrations of cotton gin byproduct (CGB). Angus steers [n = 50; initial body weight (BW) = 349 ± 66 kg) were stratified by BW and grouped in slatted floor pens (10 steers/pen). Steers were assigned randomly within pen (2 per pen) to one of five diets containing 0, 10, 20, 30, and 40% CGB (dry matter basis). Diets were balanced for protein and energy, and the steers were fed for 84 d. Steers were weighed on d -1, 0, 28, 56, 83, and 84 for the stocker phase with d -1 and 0, 83 and 84 averaged to give start and end BW. Following the growing period, steers were switched to the same finishing diet and fed for an additional 55 d prior to being transported to PA for harvest and carcass data collection. Data were analyzed using procMIXED of SASv9.4 to determine the significance of linear, quadratic, cubic, and quartic trends. During the growing phase, dry matter intake increased linearly (P = 0.0017) with 10.16, 11.23, 11.59, 11.86, and 11.96 kg/d for 0, 10, 20, 30, and 40% CGB, respectively. Average daily gain tended to increase (P = 0.0631) with a cubic trend, increasing with the first addition of CGB, declining at the intermediate levels, and then increasing again at the 40% level (1.34, 1.54, 1.36, 1.39, and 1.52 kg/d for 0, 10, 20, 30, and 40% CGB, respectively). Feed efficiency showed a similar cubic trend (P = 0.10) with 0.133, 0.138, 0.119, 0.117, and 0.128 for 0, 10, 20, 30, and 40% CGB, respectively. Within the finishing phase, average daily gain was significant (P = 0.026) as a quadratic trend with 1.54, 1.25, 1.18, 1.20, and 1.33 kg/d for 0, 10, 20, 30, and 40% CGB, respectively. Diets did not differ (P &amp;gt; 0.10) for dry matter intake (10.08 kg/d), feed conversion (8.31), or feed efficiency (0.130). Treatment did not influence (P &amp;gt; 0.10) marbling or other carcass measurements. Data suggest CGB supported good animal gains with only minor impact on feed intake and feed efficiency for stocker steers up to an inclusion rate of 40%.

PSX-16 The effect of short-term heat stress on physiological, hematological, and immunological parameters of Florida Cracker Sheep

Abstract Florida Cracker sheep are a heritage sheep breed that was developed under natural selection in Florida, US. The objective of this study was to evaluate the effect of short-term heat stress on rectal temperature, respiration rate, hematological parameters, and IgA concentrations of Florida Cracker ewes (2 yr of age). A total of fourteen ewes were allocated to heat stress (HT, n = 7) or cooling (CTL, n = 7) conditions for 6 wk during the summer season. Treatment groups were grouped in covered concrete floor pens with similar dimensions and characteristics and had access to shelter, feed, and freshwater ad libitum. The HT pen was exposed to regular ambient temperatures, and for the cooling pen, an evaporative cooling fan was used. Data for ambient temperature and relative humidity of HT and CTL pens were recorded every week to estimate the temperature humidity index (THI). Blood samples were collected from each experimental ewe 1 wk before the start of the experiment (baseline) and at wk 1, wk 2, wk 3, wk 4, wk 5, and wk 6 post-treatment. Blood samples were analyzed using a hematology analyzer (Vetscan HM5, Zoetis). Plasma was extracted from the blood and was used to evaluate IgA concentrations with a commercial kit. For the statistical analysis of the physiological, hematological, and immunological parameters, a mixed model with repeated measures was used. Fixed effects included treatment (HT or CTL), wk (1 to 6), and the treatment by week interaction. Animal was fitted as a random effect and the baseline data was used as a covariate. The THI for the HT and CTL groups ranged from 81.3 to 89.5 and from 73.5 to 75.6, respectively. The HT group presented a significant (P &amp;lt; 0.05) increase in respiratory rate when compared with the CTL group. No significant changes were observed for rectal temperature and IgA concentrations in the experimental groups. However, for wk 3, a significant (P &amp;lt; 0.05) increase of neutrophils and a decrease in lymphocyte % was observed for the HT group. In conclusion, short-term heat stress increased respiratory rate and neutrophil % and decreased the lymphocyte % in Florida Cracker ewes. It is possible that heat stress could have a detrimental impact on immune mechanisms in Florida Cracker ewes. Further studies are required to investigate the effects of long-term heat stress.

79 Microbiological effects of control measures during pork production

Abstract The objective of this study was to determine the prevalence of Shiga toxin-producing Escherichia coli (STEC) O157:H7 and efficacy of control measures at a pork processing facility. Outbreaks of E. coli O157:H7 associated with pork, though not common globally, have been reported multiple times in recent years in Alberta. Sampling at a commercial facility processing hogs was carried out at monthly intervals for 11 mo. At the facility, the dressed carcasses are sprayed with 5% lactic acid (LA) and immediately air-chilled after the LA spray. At each sampling time, 14 different types of samples were collected: dirt from the holding pen floor (n = 2), gloves of workers (n = 5), scalding water (n = 1), tonsils (n = 5), cecal material (n = 5), five swabs each from hides of animals after bleeding (HAB), and carcasses after scalding (CAS), before evisceration (CBE), after evisceration (CAE), before LA spray (BLA), after LA spray (ALA), 1h after LA spray (ALA1), 2h after LA spray (ALA2), and after chilling (ACH). All samples were enumerated for total plate count (TPC), Enterobacteriaceae, and E. coli using specific media for each. In addition, an aliquot of each sample was enriched and tested for the presence of the O-antigen gene (rfbE) for E. coli O157 and Shiga toxin-producing gene (stx1/stx2) using real-time PCR. Cultures positive for both rfbE and stx were further plated for the isolation of E. coli O157:H7. Of the 683 enrichment cultures, 12 were positive for both marker genes, from cecal material (n = 2), dirt (n = 4) and HAB (n = 6). However, none of these samples yielded STEC O157 isolates. Of these enrichment cultures, 69, 45 and 32 were positive for stx1, stx2, and both stx genes, respectively. Positive samples were mostly associated with HAB, cecal material and dirt. HAB was most and least contaminated in August/June and December, differing by 1 log unit for TPC (P &amp;lt; 0.05). Enterobacteriaceae and E. coli on HAB were also affected by month of sampling (P &amp;lt; 0.05), but this temporal trend differed from TPC (Table). The numbers for TPC, Enterobacteriaceae, and E. coli all decreased (P &amp;lt; 0.05) as the stage of carcass processing progressed. The overall reduction of TPC and E. coli was 7 and 5 log units, respectively. Scalding, LA spray and air chilling all reduced (P &amp;lt; 0.05) the numbers of indicator bacteria on carcasses. Of the 55 samples each collected from BLA, ALA, ALA1, ALA2, and ACH, 36, 13, 2, 1 and 0 were positive for E. coli, respectively. In conclusion, pork processing environments can be contaminated with STEC from hides, feces and holding pen, but levels of STEC O157 appear to be low. Scalding, LA spray and air chilling can be effective measures to reduce the risk of bacterial contamination of pork.

Research Note: Effects of on-farm and hatchery hatching on broiler performance, intestinal lesions, and immune response during a subclinical necrotic enteritis challenge

The effects of traditional and on-farm hatching systems on broiler performance and health under a subclinical necrotic enteritis (NE) challenge were evaluated in this study. A 2×2 factorial study explored the effects of place of hatch (on-farm hatched [OFH] vs. hatchery hatched [HH]) and NE challenge (nonchallenged vs. challenged) on broilers. Cobb 500 eggs (∼E19) were acquired from a commercial hatchery; 840 eggs were placed in pens on clean shavings in prewarmed floor pens and allowed to hatch out, while 927 eggs were placed in a hatcher set under standard practices. On day (d) of hatch, all chicks were weighed and randomly distributed to 4 treatments (8 replicate pens each and 30 birds/pen). The OFH birds were placed immediately after sorting while HH birds were placed back in the hatcher overnight to simulate commercial hatchery procedures. After placing HH birds, feed and litter in the challenge group pens were sprayed with a live oocyst coccidia vaccine as a predisposing factor to NE. The small intestines of 3 male chicks per pen were scored for NE lesions (n = 24) on d 8 (peak NE challenge) and jejunal samples were collected from 1 bird per pen for RNA extraction and qPCR on d 8 and d 14. Data were analyzed using JMP Pro17 and significance between treatments was identified by LSD (P ≤ 0.05). Regardless of the hatching system, the subclinical NE challenge caused a significant reduction in average daily gain (ADG) and average daily feed intake (ADFI), and increased feed conversion ratio (FCR) until d 28 (P ≤ 0.05). Moreover, OFH birds exhibited significantly better growth (P ≤ 0.05) through d 28 but had similar performance to HH birds by d 42. There were no significant differences in NE lesion scores between HH and OFH groups. In conclusion, OFH system resulted in better broiler performance compared to HH system under both no-challenge and challenge conditions during the starter and grower periods. This practice may hold potential for further exploration by the industry as an alternative to traditional hatching, aiming to improve the welfare and productivity of broilers.