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Simple Summary: The recent SARS-CoV-2 pandemic has underscored the impact of a single pathogen on public health and economic stability. Similarly, widespread disease outbreaks within agricultural animal populations are potentially devastating by producing food shortages and global starvation. Protecting agricultural animals from viral/bacterial disease outbreaks will depend on the development of countermeasures generating rapid innate immune protection. Accordingly, we have developed a rapidly deployable generalized immune stimulant activating innate immunity at mucosal sites. Past studies show that this platform, termed LTC (liposome-TLR complexes), can rapidly activate and recruit innate immune cells in rodents and companion animals. Moreover, prior rodent and cattle studies showed complete protection against lethal viral and bacterial challenge studies. In the studies described herein, we demonstrate that the LTC platform can be extended to demonstrate rapid activation of innate immune modulators from cell lines and immune cells from peripheral blood in three key agricultural animals: cattle, pigs, and poultry. Cell lines and immune cells from peripheral blood from all three of these species demonstrated significant increases in antibacterial and antiviral immune mediators when treated with LTC in vitro. These data provide justification for further testing of this platform in disease challenge models for these animals. Given the rapid potential spread of agricultural pathogens, and the lack of vaccines for many, there is an important unmet need for strategies to induce rapid and non-specific immunity against these viral and bacterial threats. One approach to the problem is to generate non-specific immune responses at mucosal surfaces to rapidly protect from entry and replication of both viral and bacterial pathogens. Using complexes of charged nanoparticle liposomes with both antiviral and antibacterial toll-like receptor (TLR) nucleic acid ligands (termed liposome-TLR complexes or LTC), we have previously demonstrated considerable induction of innate immune responses in nasal and oropharyngeal tissues and protection from viral and bacterial pathogens in mixed challenge studies in rodents, cattle, and companion animals. Therefore, in the present study, we used in vitro assays to evaluate the ability of the LTC immune stimulant to activate key innate immune pathways, particularly interferon pathways, in cattle, swine, and poultry. We found that LTC complexes induced strong production of type I interferons (IFNα and IFNβ) in both macrophages and leukocyte cultures from all three species. In addition, the LTC complexes induced the production of additional key protective cytokines (IL-6, IFNγ, and TNFα) in macrophages and leukocytes in cattle and poultry. These findings indicate that the LTC mucosal immunotherapeutic has the capability to activate key innate immune defenses in three major agricultural species and potentially induce broad protective immunity against both viral and bacterial pathogens. Additional animal challenge studies are warranted to evaluate the protective potential of LTC immunotherapy in cattle, swine, and poultry. [ABSTRACT FROM AUTHOR]

Previous studies evaluating 15 mg/kg narasin have shown improvements in BW, ADG, G:F, and HCW and carcass yield when fed for an extended period of time (>60 days). However, a detailed evaluation of feeding duration of narasin has not been completed. This study evaluated the effect of narasin feeding duration on growth performance and carcass characteristics of growing-finishing pigs. The study was carried out over a fixed time of 112 days using 1,644 pigs in a randomized complete block design. Narasin was included at 15 mg/kg in the last two, three, or four growing-finishing dietary phases, which resulted in narasin being fed for the last 68, 94, or 112 days of study and compared with a negative control diet. Pigs were fed diets that met or exceeded nutrient recommendations of growing-finishing pigs (NRC, 2012). Pigs were offered ad libitum access to feed and water throughout the study and weighed every 28 days and at every marketing event. Feed additions and feed remaining in the feeder at the time of pig weighing were recorded. Pigs were sent for harvest to a commercial slaughter facility in three marketing groups: Group 1 - 20% of pigs marketed on day 84 of study, Group 2 - 20% of pigs marketed on day 98 of study, and Group 3 - remaining 60% of pigs marketed on day 112 of study. Standard carcass grading measurements were collected for each pig and summarized by pen for data analysis. There were limited statistical differences (P > 0.05) between treatments for growth or carcass measures, likely due to the limited number of replicates (n = 16) in this research facility. Nonetheless, there were numerical improvements from feeding narasin. Final live BW (+0.3, +0.4, +1.5 kg, respectively) and ADG (+0.1, +0.4, and +1.3%, respectively; Table 1) numerically increased with increased feeding duration of narasin. Overall G:F was relatively unaffected by feeding duration. Hot carcass weight increased with increased narasin feeding duration (+0.2, +1.1, +1.9 kg, respectively), resulting in increased carcass yield with increased feeding duration (-0.2, +0.1, +0.4 percentage units, respectively). Collectively, carcass ADG and carcass G:F trended toward improvement with increased feeding duration. Results of this study confirm previously observed improvements in growth performance from extended feeding of narasin compared with controls, suggesting that a greater response to narasin is observed with longer feeding durations. [ABSTRACT FROM AUTHOR]

Our objective was to determine the effects of increasing standardized ileal digestible (SID) lysine (Lys) levels on growth performance and carcass characteristics of late-nursery-to-finish pigs sired by PIC 800 boars. Barrows and gilts [n = 1,00; PIC800×Camborough, initial body weight (BW) = 10.9 ± 0.39 kg] were used in a 142-d growth trial with 40 mixed sex pens, 10 pens per treatment, and 25 pigs per pen. At the beginning of the trial, pens were blocked by BW and randomly allotted to one of four treatments (overall dietary SID Lys level as 87, 95, 102, or 110% of PIC SID Lys recommendations) in a randomized complete block design. Diets were corn-soybean meal (SBM)-based, and treatments were achieved through the inclusion of SBM with adjustments of corn and choice white grease. Diets were fed in 7 phases (11-17, 17-34, 34-44, 44-57, 57-77, 77-95, and 95-133 kg) and formulated to be iso-caloric across treatments for each phase. Within each phase, only the diets of the least and greatest SID Lys levels were manufactured, and the diets of intermediate SID Lys levels were blended by the automatic feeding system in the research facility. Growth performance data were analyzed using the GLIMMIX procedure in SAS (Version 9.4, SAS Institute, Inc., Cary, NC) and considered pen as the experimental unit. The statistical model considered fixed effects of SID Lys levels and random effects of the block. Mortality and removals were also analyzed using the GLIMMIX procedure and specified a binomial distribution. All data are reported as least square means and considered statistically significant at P < 0.05 and marginally significant at P < 0.10. Increasing overall dietary SID Lys levels reduced overall average daily feed intake (linear, P = 0.045) and increased overall gain-to-feed ratio (linear, P = 0.002), but there was no evidence for a difference across treatments for overall average daily gain (P > 0.10) or overall removal and mortality rate (Table 1; P >0.10). Pigs fed overall SID Lys level as 102% of PIC recommendation had significantly greater carcass yield compared with those fed 95 or 110% (P < 0.05), with the pigs fed 87% being intermediate. Increasing overall dietary SID Lys levels reduced backfat depth (linear, P< 0.001) and increased lean yield (linear, P = 0.012), but there was no evidence for a difference among treatments for loin depth (P > 0.10). In conclusion, increasing overall dietary SID Lys level beyond PIC recommendations through increasing SBM levels resulted in improved feed efficiency, backfat depth, and lean yield of 11 to 133 kg pigs sired by PIC 800 boars. [ABSTRACT FROM AUTHOR]

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Two studies were conducted to estimate the SID Thr:Lys requirement for growth and feed efficiency of PIC 337×1050 pigs from approximately 12- to 70-kg. In Exp. 1, 987 pigs [initial body weight (BW) = 11.8±0.32 kg] were used from 12- to 24-kg. In Exp. 2,875 pigs (initial BW = 43.4±0.58 kg] were used from 43- to 70-kg. Pens of pigs were blocked by BW and randomly allotted to dietary treatments in randomized complete block designs, with 21 to 27 pigs per pen with 8 and 7 replications per treatment (Exp. 1 and 2, respectively). Pens were provided 1 of 5 dietary treatments with increasing SID Thr:Lys ratios at 53, 58, 62, 65, and 68% in each experiment. Two corn-soybean meal-based diets containing 53 and 68% Thr:Lys ratios were blended to achieve target SID Thr:Lys treatment levels in each experiment. In Exp. 1 (12- to 24-kg), ADG and final BW increased (linear, P = 0.006) while ADFI, G:F, Thr intake/d, and Thr intake/kg of gain increased (quadratic, P = 0.001) as Thr:Lys ratio increased (Table). Additionally, Lys intake/d increased (quadratic, P < 0.001) while Lys intake/kg of gain decreased (quadratic, P < 0.001) with increasing Thr:Lys ratio. In Exp. 2 (43- to 70-kg), ADG, G:F, final BW, Thr intake/d and Thr intake/kg of gain also increased (linear, P = 0.036) as dietary Thr:Lys increased. Moreover, Lys intake/kg of gain decreased (linear, P = 0.023) with increasing Thr:Lys. A quadratic polynomial (QP) model predicted a requirement at levels greater than 68% SID Thr:Lys for ADG from 12- to 24-kg, while a QP model suggested that maximum G:F was achieved at 61.8% SID Thr:Lys (Exp. 1). From 43- to 70-kg, QP models suggested maximum ADG and G:F were achieved at levels greater than 68% SID Thr:Lys (Exp. 2). However, similar fitting BLL models predicted no further improvement to G:F and ADG beyond 65 and 67% SID Thr:Lys, respectively. In summary, these results suggest the optimal SID Thr:Lys for 12- to 24-kg pigs is 61.8% for feed efficiency and greater than 68% for ADG. From 43- to 70-kg, the requirement was predicted at or above 65 and 67% SID Thr:Lys for G:F and ADG, respectively. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate growth performance and economic return of PIC 800 × Camborough pigs fed increasing SID Lys from approximately 12- to 136-kg. Pens of pigs were blocked by body weight (BW) and randomly assigned to 1 of 5 dietary treatments in a randomized complete block design with 26 pigs per pen and 16 pens per treatment. Pens were provided 1 of 5 dietary treatments with increasing SID Lys at 85, 93, 100, 107, and 115% of current (2021) PIC recommendations within 6 dietary phases as follows: phase 1 (1.09, 1.19, 1.28, 1.36, and 1.47%), phase 2 (0.97, 1.06, 1.14, 1.22, and 1.32%), phase 3 (0.87, 0.95, 1.02, 1.09, and 1.17%), phase 4 (0.75, 0.82, 0.88, 0.94, and 1.01%), phase 5 (0.66, 0.72, 0.77, 0.82, and 0.89%), and phase 6 (0.59, 0.64, 0.69, 0.74, and 0.79%). Two corn-soybean meal-based diets containing low and high Lys were blended to achieve target SID Lys levels for each treatment diet within phase. Overall (d 0 to 143), increasing SID Lys improved (linear, P = 0.007) ADG and G:F, but did not impact ADFI (P > 0.10; Table). A tendency (linear, P = 0.067) for heavier hot carcass weights (HCW) was observed in pigs fed increasing SID Lys. However, there was no evidence for differences (P > 0.10) in carcass yield, backfat depth, loin depth, or carcass lean percentage across treatments. The linear (LM) model served as the best fit for both growth and economic parameters. The LM model predicted maximum ADG and G:F at levels greater than 115% of PIC's current recommendations. However, for income over feed cost (IOFC), the LM model predicted maximum profitability at or below 85% of the current Lys recommendations of PIC. In conclusion, the optimal SID Lys level for PIC 800 × Camborough pigs from 12- to 136-kg differed upon response criteria, with growth performance maximized at levels at or above 115% of the recommendation for SID Lys by PIC; however, maximal economic returns were observed at or below 85% of PIC's current SID Lys recommendations. [ABSTRACT FROM AUTHOR]

Our objective was to determine the effects of increasing standardized ileal digestible (SID) lysine (Lys) levels on growth performance and carcass characteristics of growing-finishing pigs. A total of 1,013 barrows and gilts (PIC337×Camborough, initially 29.2±0.21 kg) were used in a 112-d growth trial with 25 or 26 pigs per pen and 13 pens per treatment in a randomized complete block design. Diets were corn-soybean meal (SBM)-dried distillers grains with solubles-based, and treatments were achieved through the inclusion of SBM at the expense of corn. Diets were fed in 6 phases and formulated to be iso-caloric within each phase. Treatments consisted of: 1) Low Lys: overall dietary SID Lys levels as 87% of PIC2016 Lys requirement; 2) Medium Lys: overall dietary SID Lys levels as 97% of PIC2016 Lys requirement; 3) High Lys: overall dietary SID Lys levels as 106% of PIC2016 Lys requirement. Experimental data were analyzed using generalized linear mixed models with pen as the experimental unit. Pigs fed High or Medium Lys had greater (P< 0.01) average daily gain compared to pigs fed Low Lys. There was no evidence (P >0.10) for the difference between treatments for average daily feed intake. Pigs fed High Lys had the greatest (P< 0.01) feed efficiency (G:F) followed by Medium Lys, with pigs fed Low Lys with the lowest G:F. Pigs fed High or Medium Lys had greater (P< 0.01) hot carcass weight, loin depth, and lean percentage compared to pigs fed Low Lys. There was no evidence (P >0.10) for treatment effect on carcass yield and backfat. Pigs fed Low Lys had greater removal and mortality rate than those fed High or Medium Lys (P< 0.01). In conclusion, increasing SID Lys over PIC2016 recommendations through increasing SBM levels resulted in increased growth performance and carcass characteristics, and reduced removal and mortality rate of 29- to- 129 kg pigs. [ABSTRACT FROM AUTHOR]

• Transmission was detected 6 weeks after contact to a naturally infected gilt. • Differences in time-to-detection of M. hyopneumoniae were observed among sample types. • Likelihood of missing M. hyopneumoniae infection was dependent on sample type. Mycoplasma hyopneumoniae (M. hyopneumoniae) continues to be a prevalent and economically important swine respiratory pathogen. For M. hyopneumoniae surveillance, blood samples and/or oral fluids are commonly collected from incoming replacement gilts prior to entering sow farms. However, limitations to this approach exist, particularly due to low sensitivity during acute stages of natural infection, leading to diagnostic uncertainty. Therefore, the objective of this study was to evaluate the natural transmission and detection of M. hyopneumoniae based on the introduction of one infected gilt to a naïve population. Twenty-nine naïve gilts were housed with one M. hyopneumoniae naturally exposed gilt for 8 weeks. Deep tracheal catheters, laryngeal swabs, and blood samples were individually collected from each gilt at 0, 1, 2, 4, 6, and 8 weeks post-contact (wpc), along with one pen-based oral fluid sample. Blood samples were assayed by ELISA, while all other samples were tested by real-time PCR. The transmission rate of M. hyopneumoniae (ꞵ) was estimated using a Bayesian mixed-effects generalized linear model. At 8 wpc, 27 % (8/29) of the naïve gilts had become infected (ꞵ = 0.73 new infected gilts/gilt-week). Seroconversion was detected in 3% of contact gilts at 8 wpc. Oral fluids were negative for M. hyopneumoniae at all samplings. In this study, the natural transmission of M. hyopneumoniae was slow and detection varied based on sample type and timing. Thus, M. hyopneumoniae surveillance protocols should include lower respiratory tract samples that are tested by real-time PCR to avoid the introduction of potentially infected gilts into naïve sow farms. [ABSTRACT FROM AUTHOR]