Chromium Methionine and Ractopamine Supplementation in Summer Diets for Grower-Finisher Pigs Reared under Heat Stress

This study aimed to determine the effects of the dietary supplementation of chromium methionine (CrMet) and ractopamine (RAC) on pigs in the growing-finishing stage under heat stress. The parameters evaluated included productive behavior, blood components, carcass characteristics, organ weight, and meat quality. This study was conducted during the summer season in Sonora, Mexico. The treatments included: (1) control diet (CON), a base diet (BD) formulated to satisfy the nutritional requirements of pigs; (2) RAC, BD plus 10 ppm RAC supplemented during the last 34 days of the study; (3) CrMet-S, BD supplemented with 0.8 ppm of Cr from CrMet during the last 34 days; and (4) CrMet-L, BD supplemented with 0.8 ppm of Cr from CrMet for an 81 d period. RAC supplementation improved the productive behavior and main carcass characteristics of the pigs compared with CON. However, RAC and CrMet supplementation during the last 34 days showed similar results in terms of weight gain, carcass quality, blood components, organ weight, and meat quality. The addition of CrMet-S had a moderate (although not significant) increase in productive performance and carcass weight. These findings are encouraging, as they suggest that CrMet may be a potential alternative for growth promotion. However, more research is needed.

Productive Performance, Physiological Variables, and Carcass Quality of Finishing Pigs Supplemented with Ferulic Acid and Grape Pomace under Heat Stress Conditions

The effect of individual and combined supplementation of FA and GPM on physiological variables, productive performance, and carcass characteristics of finishing pigs under heat stress conditions were investigated. Forty Yorkshire × Duroc pigs (80.23 kg) were individually housed and randomly distributed into 4 groups under a 2 × 2 factorial arrangement (n = 10): Control (basal diet, BD); FA, BD + 25 mg FA; GPM, BD with 2.5% GPM; and MIX, BD with 25 mg FA and 2.5% GPM. Additives were supplemented for 31 days. The inclusion of FA or GPM did not modify rectal temperature and respiratory rate. There was an effect of the interaction on FI, which increased when only GPM was supplemented, with respect to Control and MIX (p < 0.05). Average daily gain (ADG) and feed conversion (FC) were not affected by treatments (p > 0.05). The inclusion of FA improved hot and cold carcass weight, while the addition of GPM decreased the marbling (p < 0.05) and tended to increase loin area (p < 0.10). GPM increased liver weight (p < 0.05). The addition of GPM and FA can improve some carcass characteristics under heat stress conditions. It is necessary to continue investigating different levels of inclusion of GPM and FA in finishing pigs' diets.

Effects of Ferulic Acid Supplementation on Growth Performance, Carcass Traits and Histochemical Characteristics of Muscle Fibers in Finishing Pigs

FA dietary supplementation on the growth performance, carcass traits and histochemical characteristics of the Longissimus thoracis muscle from finishing pigs was investigated. Four hundred and twenty pigs were used in this study, and 105 animals (with five replicate pens and 21 pigs per pen) were assigned to one of four treatments: basal diet (BD) without additives (C-); BD + 10 ppm ractopamine hydrochloride + 0.97% lysine (C+); BD + 25 ppm of FA (FA); and BD + 25 ppm of FA + 0.97% lysine (FA-Lys). Dietary supplementation with FA or ractopamine increased both the average daily gain (14%) and loin muscle area (19%), while fat deposition decreased by 53%, in comparison with C- (p < 0.05). The growth performance of pigs treated with FA was similar to those of ractopamine (p > 0.05). The histochemical analysis showed that FA and C+ treatments induced a shift in muscle fiber types: from fast fibers to intermediate (alkaline ATPase) and from oxidative to glycolytic fibers. Muscle tissues from animals treated with FA or ractopamine had a lower cross-sectional area and a greater number of muscle fibers per area (p < 0.05). Findings regarding growth performance and carcass traits indicate that FA supplementation at 25 ppm without extra-lysine can replace the use of ractopamine as a growth promoter in finishing pigs.

Individual training for farmers based on results from protein and ATP rapid tests and microbiological conventional cultural methods improves hygiene in pig fattening pens

Optimal hygiene management is an essential part of maintaining a high standard of health in conventional pig production systems and for the successful interruption of infection chains. Currently, efficiency assessments on cleaning and disinfection are only performed by visual inspection or are neglected completely. The aim of this study was to evaluate the available methods for on farm monitoring of hygiene, identify critical points in pig pens and use the data obtained for training purposes. In addition to visual inspection by assessing the cleanliness, microbiological swab samples, i.e., aerobic total viable count (TVC), total coliform count, methicillin-resistant Staphylococcus aureus (MRSA), and extended-spectrum β-lactamases-producing bacteria (ESBL), swab samples for ATP as well as protein residues and agar contact plates combined with 3 different culture media, were applied and ranked according to their suitability for livestock farming. Samples were collected on at least 15 critical points from one representative pen on 6 pig fattening farms with various hygiene management practices after cleaning and disinfection. After the first sampling, farmers were trained with their individual results, and sampling was repeated 6 mo after training. Nipple drinkers, feeding tubes (external and inner surface), and troughs (external and inner surface) showed the greatest bacterial loads (TVC: 4.5-6.7 log10 cfu cm-2) and values for ATP and protein residues; therefore, these surfaces could be identified as the most important critical points. Spearman rank correlations (P < 0.01) were found between the different assessment methods, especially for the TVC and ATP (r = 0.82, P < 0.001). For rapid assessment on farms, ATP tests represented an accurate and cost-efficient alternative to microbiological techniques. Training improved cleaning performance as indicated by a lower rating for visual inspection, TVC, ATP, MRSA, and ESBL in the second assessment. The monitoring of cleaning efficiency in pig pens followed by training of the staff constitutes a valuable strategy to limit the spread of infectious diseases and antibiotic-resistant bacteria. Special attention should be paid to the sufficient hygiene of drinkers and feeders.

Association Between agr Type, Virulence Factors, Biofilm Formation and Antibiotic Resistance of Staphylococcus aureus Isolates From Pork Production

Livestock-associated Staphylococcus aureus colonization and/or infections exist in pigs and people in frequent contact with pigs. In this study, a total of 130 S. aureus isolates obtained from different stages of pork production were subjected to antimicrobial susceptibility, biofilm formation, as well as PCR screening to identify virulence genes, and the accessory gene regulator alleles (agr). Among all 130 S. aureus isolates, 109 (83.8%, 109/130) isolates were positive for agr. All swine farms isolates belonged to agr IV, whereas S. aureus isolated from slaughterhouse and retail indicated diverse agr types. All isolates exhibited biofilm formation ability, and raw meat isolates (belonging to agr I) exhibited a greater ability to form strong biofilms than swine farms isolates (belonging to agr IV). agr-positive isolates were associated with more virulence genes than agr-negative isolates. Most biofilm-producing isolates were positive for microbial surface component recognizing adhesive matrix molecule (MSCRAMM), capsule type and ica group genes. The results illustrate a significant association between the prevalence rate of MSCRAMM, capsule type and ica group genes among isolates producing weak, moderate and strong biofilms. The high prevalence of resistance to ciprofloxacin, gentamicin, tetracycline, clarithromycin, clindamycin, and trimethoprim-sulfamethoxazole were mainly observed in moderate and weak biofilm producers. Our findings indicate that S. aureus isolates from pork production displayed diverse molecular ecology.

Prevalence of Enterotoxin Genes in Staphylococcus aureus Isolates from Pork Production

In this study, 130 Staphylococcus aureus isolates from samples associated with pork production were tested for prevalence of 18 staphylococcal enterotoxin (SE) genes. Approximately 94.6% (123/130) of isolates from different stages of pork production harbored one or more SE genes forming 37 different enterotoxin gene profiles. Seb was present in 60.0% of the S. aureus isolates, the highest among the genes tested. The genes, sed, sej, seo, sep, ser, and seu, were not found. The five classical SE genes (including sea, seb, sec, sed, see) had lower prevalence than the egc gene cluster (seg, sei, sem, sen, seo, or seu). Notably, ∼6.9% (9/130) isolates harbored five SE genes. Classical SE genes were relatively higher in raw meat isolates than swine farm isolates, suggesting that raw meat isolates have a greater potential for classical staphylococcal food poisoning. Incomplete egc clusters were mainly distributed in swine farm isolates, and some of them coexisted with other classical SE genes (seb, sec), showing that swine farms could be potential sources of enterogenic S. aureus of food safety concern. Characterizing the distributions of enterotoxin genes among S. aureus may provide epidemiological information for the benefit of public health and food safety.

Penile Injuries in Wild and Domestic Pigs

Simple Summary

Male pigs raised for pork production on experimental and commercial farms were evaluated for scars, fresh wounds and severe injuries of the penis. A high incidence of penile injuries (64.0%–94.9% of the animals/farm) was found in boars but not in barrows (castrated males) with even severe wounds in 5.2% to 9.3% of the boars. A similar evaluation of 15 free-ranging wild boars also revealed a considerable proportion of animals with penile injuries. Thus, penis biting is a highly relevant and severe welfare problem in boars which is not limited to intensive production systems.

Abstract

In boars, sexually motivated mounting can not only cause problems such as lameness, but penile injuries are also reported. The relevance of penis biting in boars is discussed controversially, but reliable data is missing. In the present study, boars (n = 385) and barrows (n = 85) from experimental farms were therefore evaluated for scars, fresh wounds and severe injuries of the penis. Similarly, 321 boars from 11 farms specializing in pork production with boars, and 15 sexually mature wild boars from the hunting season of 2015/16 were included in the study. In domestic boars, a high incidence of penile injuries was obvious (76.6%–91.3% of animals with scars and/or wounds at experimental farms, 64.0%–94.9% at commercial farms). The number of boars with severe injuries was in a similar range in both groups (5.2% vs. 9.3%). At commercial farms, the number of scars but not that of fresh wounds increased per animal with age by 0.3 per week. Moreover, raising boars in mixed groups led to about a 1.5 times higher number of scars than in single-sex groups. In wild boars, a considerable proportion of animals (40%) revealed penile injuries, which were even severe in three animals. We therefore conclude that penis biting is a highly relevant and severe welfare problem in the male pig population, but this phenomenon is not limited to intensive production systems.