Effects of Antibiotics and Probiotics on Suckling Pig and Weaned Pig Performance Mark J. Estienne, PhD1 Thomas G. Hartsock, PhD2 Allen F. Harper, PhD1 1Department of Animal and Poultry Sciences Virginia Polytechnic Institute and State University Blacksburg, Virginia 2Department of Animal and Avian Sciences University of Maryland College Park, Maryland KEY WORDS: pigs, probiotic, antibiotic from different litters (MIXED) or littermate pigs (NON-MIXED). Treatments included: ABSTRACT 1) probiotic (4 mL) and NON-MIXED pigs, Effects of various antibiotics or a probiotic 2) vehicle and NON-MIXED pigs, 3) probi- on growth and death loss in suckling pigs otic and MIXED pigs, and 4) vehicle and and the effect of a probiotic on nursery MIXED pigs. Probiotic or vehicle was pig performance were determined. In administered as an oral gavage on the day Experiment 1, suckling pigs received either of weaning; there were 4 pens per treatment. oxytetracycline (n = 21), erythromycin There were tendencies for effects of treat- (n = 21), penicillin G procaine (n = 21), or ment × grouping for average daily gain tylosin (n = 22) i.m., or no antibiotic (n = (P = 0.11) and feed consumed (P = 0.12). 21), within 24 hours after farrowing. There For MIXED pens, there was an effect of was no effect of treatment (P = 0.83) on probiotic treatment on average daily gain survival until weaning, and pig body (P = 0.05) and feed consumed (approached weights at 7 (P = 0.84), 14 (P = 0.96), and significance, P = 0.08). In summary, admin- 21 (P = 0.90) days of age were not different istration of antibiotics or probiotics to among groups. In Experiment 2, suckling neonatal pigs showed no benefit on pre- pigs received an oral gavage of 2 mL of weaning performance. However, a probiotic tended to enhance average daily probiotic (5 × 1 0 6 lactobacillus and strepto- coccus colony forming units/mL) (n = 94) gain and feed consumption in pigs that were or vegetable oil (n = 87) within 24 hours weaned into pens with non-littermates. after farrowing. There was no effect of treatment (P = 0.65) on survival until wean- INTRODUCTION ing, and pig body weight at 7 (P = 0.63), 14 Efficient and profitable operation of com- (P = 0.55), and 21 (P = 0.24) days of age mercial swine units is often limited by high were not different between groups. In mortality, morbidity, and poor performance Experiment 3, weaned pigs were placed in in suckling pigs and pigs in the nursery nursery pens (4 pigs/pen) with either pigs phase of production. Death losses of pre- Intern J Appl Res Vet Med • Vol. 3, No. 4, 2005 303 weaning pigs and nursery pigs are typically MATERIALS AND METHODS 12.2% and 2.4%, respectively.1 M o r e o v e r , All experiments were conducted at the 0.4% of pigs classified as “stunted” because University of Maryland Eastern Shore of un-thriftiness or poor growth are Swine Research and Education Facility removed from nurseries nationwide.1 (Princess Anne, MD) and protocols were Antibiotics are routinely used on North approved by the Institutional Animal Care American swine farms and are administered and Use Committee. in the form of medicated water or as feed Experiment 1 additives. The addition of antimicrobial products to nursery feeds is especially The objective was to determine the effects effective with typical improvements in of various antibiotics, administered within growth rates and feed conversion efficien- 24 hours after farrowing, on growth and cies of up to 16% and 6%, respectively.2 death loss in suckling pigs. Nine multi- Industry surveys suggest that more than parous Yorkshire sows were mated to 82% of U.S. swine farms with nursery pigs Yorkshire or Poland China boars and were use antimicrobial feed additives in diet for- moved on approximately Day 110 of gesta- mulations.3 And although few experiments tion to individual farrowing crates in an environmentally controlled, mechanically have been conducted to assess effects on ventilated building. During lactation, sows performance, suckling pigs on more than had ad libitum access to water and a com- 44% of all operations are routinely given mercially prepared diet (Southern States injectable antibiotics during post-farrowing Cooperative, Baltimore, MD) that met or processing or at weaning for prophylactic exceeded the recommendations for the vari- and treatment purposes.4 ous nutrients as put forth by the National Because of the concern that resistant Research Council.6 Sows farrowed a total microbes may develop that compromise the of 106 live pigs (11.8 pigs/litter) that were effectiveness of antibiotics for treating utilized in the experiment. human and animal diseases, the routine use Within 24 hours after farrowing, pigs were of antibiotics on commercial swine farms subjected to the following processing proce- faces an uncertain future. For example, the dures: ears notched for identification, needle U.S. Food and Drug Administration has teeth resected, tails docked, and injected with called for an extensive re-evaluation of con- 200 mg iron dextran (Iron Hydrogenated tinued use of antimicrobial feed additives.5 Dextran; Duravet, Inc., Blue Springs, MO). Excessive and improper use of injectable Additionally, pigs within each litter received antibiotics is also a concern. Thus, there is an i.m. injection of either oxytetracycline (20 interest in alternatives to antibacterial prod- mg/kg body weight; Liquamycin; Pfizer ucts such as probiotics. Probiotics are viable Animal Health, New York, NY) (n = 21), microbial cultures that purportedly increase erythromycin (8.6 mg/kg body weight; the gastrointestinal population of beneficial Gallimycin; AgriLabs, St. Josephs, MO) (n = bacteria that competitively exclude bacteria 21), penicillin G procaine (6667 units/kg body that may compromise health and growth weight; Agri-cillin; AgriLabs) (n = 21), or p e r f o r m a n c e . 2 tylosin (8.9 mg/kg body weight; Tylan-50; The objectives of the experiments Elanco Animal Health, Indianapolis, IN) (n = described herein were to determine the 22). Remaining pigs (n = 21) received no effects of injectable antibiotics or a probiot- antibiotic and served as untreated controls. ic, administered within 24 hours after far- Pigs were weighed at birth and at 7, 14, and rowing, on growth and death loss in 21 (weaning) days of age. suckling pigs and to determine the effect of a probiotic, administered at weaning, on Experiment 2 nursery pig performance. The objective was to determine the effects 304 Intern J Appl Res Vet Med • Vol. 3, No. 4, 2005 of a probiotic, administered within 24 hours istered to NON-MIXED pigs, 3) probiotic after farrowing, on growth and death loss in administered to MIXED pigs, and 4) vehicle suckling pigs. Multiparous Yorkshire sows administered to MIXED pigs. Probiotic (n = 10) and Yorkshire gilts (n = 10) were (Probios Oral Suspension; 4 mL; mated to Yorkshire or Poland China boars 5 × 1 0 6 lactobacillus and streptococcus colony and were moved on approximately Day 110 forming units/mL) or vehicle was adminis- of gestation to individual farrowing crates. tered as an oral gavage on the day of weaning. During lactation, sows were fed as During the 3-week trial, pigs were described for Experiment 1. Sows farrowed allowed ad libitum access to commercially a total of 181 live pigs (9.1 pigs/litter) that prepared nursery diets (Southern States were utilized in the experiment. Cooperative). A Phase I diet was fed during Within 24 hours after farrowing, pigs Week 1, and a Phase II diet was fed during were subjected to the following processing Weeks 2 and 3. Pigs were weighed on the procedures: ears notched for identification, day of weaning (Week 0) and at the end of needle teeth resected, tails docked, and Weeks 1, 2, and 3. Pen feed consumption injected with 100 mg iron dextran. and feed conversion efficiency (Feed:Gain) Additionally, pigs within each litter received were determined at the end of the trial. an oral gavage of 2 mL of probiotic Statistical Analyses (Probios Oral Suspension; Chr. Hansen For Experiments 1 and 2, pig weights at Biosystems, Milwaukee, WI; 5 × 1 0 6 l a c t o- birth and at 7, 14, and 21 days of age were bacillus and streptococcus colony forming subjected to analysis of variance for a ran- units/mL) (n = 94) or vegetable oil (n = 87). domized block design using the generalized Pigs were weighed at birth and at 7, 14, and linear models procedure of SAS (SAS 21 (weaning) days of age. Institute Inc., Cary, NC). The model includ- Experiment 3 ed treatment and litter (block) as possible The objective was to determine the effects sources of variation. Pre-weaning death loss of a probiotic, administered at weaning, on for the various treatments was compared growth performance in nursery pigs. We using chi-square analysis. hypothesized that potential positive effects For Experiment 3, pig weights at wean- of the probiotic may be more evident in pigs ing (Week 0), Weeks 1, 2, and 3, average subjected to the stress of mixing littermates daily gain, feed consumed, and feed conver- at weaning. Thus, pigs in this study were sion efficiency were subjected to analysis of grouped in pens either with pigs from dif- variance. The model included treatment ferent litters (MIXED) or littermate pigs (probiotic or vehicle) and grouping ( N O N - M I X E D ) . (MIXED or NON-MIXED) and treatment × Yorkshire pigs were weaned at 28.9 ± grouping as possible sources of variation. 0.5 days of age into a clean, disinfected nursery with supplemental heat and a nega- RESULTS AND DISCUSSION tive pressure ventilation system. Pens were Experiment 1 equipped with Tribar metal flooring (Hog Shortly after birth, pigs on commercial opera- Slat Inc., Newton Grove, NC), a nipple tions are often subjected to a variety of proce- drinker, and a standard nursery feeder.