Administration of Lactobacillus johnsonii FI9785 to chickens affects colonisation by Campylobacter jejuni and the intestinal microbiota

1. Campylobacter jejuni is the most common bacterial cause of human food-borne gastroenteritis in the world. A major source of human infection is the consumption of contaminated meat, particularly poultry. New control measures to reduce or eliminate this pathogen from the animal gastrointestinal tract are urgently required, and the use of probiotics as competitive exclusion agents is a promising biocontrol measure to reduce C. jejuni in the food chain.

2. In this study, we assessed the potential of Lactobacillus johnsonii FI9785, which has shown efficacy against Clostridium perfringens, to combat C. jejuni. The effect of prophylactic administration of L. johnsonii on the ability of C. jejuni to colonise chickens was determined.

3. Two doses of L. johnsonii given a week apart led to a reduction in C. jejuni colonisation in the caecal contents, but this biocontrol seemed reliant upon a high level of initial colonisation by the probiotic.

4. The microbial composition in the chicken gut was significantly altered by the probiotic treatment, as shown by denaturing gradient gel electrophoresis of 16S rRNA gene amplicons.

5. Together these results demonstrate the potential of this probiotic strain to be tested further as a competitive exclusion agent in poultry against C. jejuni.     

REVIEW ARTICLE: An integrated view on how the management of the dry period length of lactating cows could affect mammary biology and defence

The dry period is necessary to facilitate cell turnover in the bovine mammary gland and to optimize milk production in the next lactation. An 8‐week dry period has long been the golden standard of management for dairy cows. Genetic improvements and new management technologies have led to higher milk production and a need for re‐evaluation of the dry period length. Over the last decade, dry period length has been proposed to be shortened or eliminated mainly from an economic point of view. However, the influence of modified dry period length on the immune defence of the bovine mammary gland and the occurrence of new intramammary infections has not yet been appreciated. The objective of this review is to discuss the bovine mammary gland biology, defence and systemic health when the dry period length is modified. Shortening or eliminating the dry period may minimize or remove the impact of milk accumulation at dry off, thereby lessening the immunodeficiency of the dam that is characteristic of this period. Composition of mammary secretions may change and the extent of tissue remodelling may be reduced when the dry period is reduced or eliminated. Additionally, impact of the dry period length on energy and nutritional status, and on hormonal and local regulatory factors, lead us to hypothesize that changing the dry period length might also affect the response to intramammary infection. It is concluded that there is a need to integrate mammary gland biology and defence mechanisms in studies dealing with modified dry period lengths.     

Long‐term Effects of Pyrethrin and Cyfluthrin,a Type II Synthetic Pyrethroid,Insecticide Applications on Bull Reproductive Parameters

The objectives of this study were to determine effects of cyfluthrin and pyrethrin spray products, used in combination with cyfluthrin topical and ear tag applications, on bull reproductive parameters over 18 weeks. Angus or Angus x Simmental bulls were randomly assigned to one of three treatment groups: (i) no exposure to pyrethrins/cyfluthrin (CONT; n = 10), (ii) cyfluthrin ear tag and topical applications (ET; n = 10), or (iii) cyfluthrin ear tag, topical, premise spray and pyrethrin fog spray applications (ET+S; n = 8). Bull body weight was measured every 3 week, and body condition score and scrotal circumference were recorded on weeks 0, 9 and 18. Semen and serum were collected every 3 weeks for sperm evaluation and testosterone measurement, respectively. There was a treatment × week interaction (p < 0.01) for sperm with primary defects; bulls in CONT group had a greater (p = 0.01) percentage of sperm with primary defects than bulls treated with insecticides at week 18. Overall and progressive sperm motility, normal sperm morphology, secondary sperm defects and serum testosterone concentrations changed (p < 0.01) over time in all bulls; however, treatment did not affect (p ≥ 0.13) any of these parameters. There were also no treatment effects (p ≥ 0.08) on bull body weight, body condition score or scrotal circumference. The use of pyrethrin‐ and cyfluthrin‐based insecticides, regardless of application, did not negatively affect reproductive parameters in beef bulls when administered over 18 weeks.     

Episodic weakness associated with exertional lactic acidosis and myopathy in Old English sheepdog littermates.

Two Old English Sheepdog littermates were evaluated for weakness that developed during periods of minimally intense exercise. Lactic acidosis accompanied by increased muscle enzyme activity, an increased lactate/pyruvate ratio, and increased venous PO2 supported the possibility of defective mitochondrial oxygen use. Electromyographic abnormalities included increased insertional activity and complex repetitive discharges. Muscle alterations included scattered myofiber necrosis, abundant endomysial connective tissue, excessive glycogen accumulation, and greater than normal numbers and vacuolation of mitochondria. A distinctive pattern of subsarcolemmal mitochondrial aggregates, referred to as "ragged red fibers" in human mitochondrial myopathies, was observed in muscle biopsy samples from 1 dog. Several features of the disease in these dogs, including onset of weakness during early life, simultaneous disease in littermates, subtle nonprogressive weakness of at least 3 years' duration, and partial reversibility of lactic acidosis following rest were suggestive of an inborn error of metabolism, consistent with mitochondrial myopathy.     

The Oxidative Stress,Antioxidant Profile and Acid–base Status in Preterm and Term Canine Neonates

During the initiation of neonatal pulmonary respiration, there is an exponential increase in reactive oxygen species that must be scavenged by antioxidant defences. However, neonate and preterm newborns are known to possess immature antioxidant mechanisms to neutralize these toxic effects. The purposes of this study were to compare the development of antioxidant system between preterm and term canine neonates and to evaluate the magnitude of acid–base balance during the initial 4 h of life. A prospective study was conducted involving 18 neonatal puppies assigned to Term Group (63 days of gestation; n = 5), Preterm‐57 Group (57 days of gestation; n = 8) and Preterm‐55 Group (55 days of gestation; n = 5). Neonates were physically examined through Apgar score and venous haemogasometry within 5 min, 2 and 4 h after birth. No difference on amniotic fluid and serum superoxide dismutase (SOD), glutathione peroxidase (GPx) and the marker of oxidative stress (thiobarbituric acid reactive substances; TBARS) was verified. Irrespective of prematurity, all neonates presented low vitality, hypothermia, acidosis, hypoxaemia and hypercapnia at birth. However, term puppies clinically evolved more rapidly than preterm newborns. During the course of the study, premature neonates presented more severe complications, such as prolonged hypoxaemia and even death. In conclusion, premature puppies have no signs of immature enzymatic mechanisms for controlling oxidative stress, although SOD and GPx may participate in achieving acid–base balance. Aside from initial unremarkable symptoms, premature puppies should be carefully followed up, as they are at high risk of succumbing to odds of prematurity.     

Molecular definition of the bovine granulocytopathy syndrome: identification of deficiency of the Mac-1 (CD11b/CD18) glycoprotein

Leukocytosis (34,600 WBC/microliter of blood) was detected in an apparently healthy 7-day-old Holstein heifer. Analysis of blood samples obtained over the next 41 days revealed chronic progressive neutrophilia, which peaked at greater than 85% neutrophils and exceeded 100,000 WBC/microliter. In vitro assessment of isolated blood neutrophils obtained from the heifer at 38 and 45 days of age revealed selected functional abnormalities. Endocytosis of immunoglobulin-opsonized Staphylococcus aureus and killing of this test organism by the calf's neutrophils were significantly diminished, as were phagocytosis-associated superoxide generation, chemiluminescence activity, and myeloperoxidase-catalyzed iodination. Diminished H2O2 elaboration by the calf's neutrophils was evident during ingestion of opsonized zymosan or on exposure to phorbol myristate acetate. Extracellular release (secretion) of elastase during ingestion of zymosan was also diminished, although total cell content of elastase was normal, compared with that of neutrophils from age-matched calves, and granular or other morphologic abnormalities of the calf's neutrophils were not evident by ultrastructural examination. Abnormalities of random migration were inconsistently detected, and normal or high degree of antibody-dependent cytotoxicity or natural killing by the calf's neutrophils was observed. Similar in vitro assessment of neutrophils obtained from the calf's dam revealed no functional abnormalities. The calf died at 48 days of age, with persistent fever and chronic diarrhea, despite administration of antibiotics. Histologic examination at necropsy revealed large numbers of intravascular neutrophils in most tissues, including massive neutrophil sequestration in spleen. However, a striking lack of extravascular neutrophils was evident in inflamed submucosa adjacent to intestinal ulcers heavily contaminated with enteric microorganisms. Bone marrow examination revealed diffuse myeloid hyperplasia, but no other abnormalities.     

Serum fructosamine concentration in nondiabetic and diabetic cats

Differentiating transient hyperglycemia from diabetic hyperglycemia can be difficult in cats since single blood glucose measurements reflect only momentary glucose concentrations, and values may be elevated because of stress-induced hyperglycemia. Glycated protein measurements serve as monitors of longer-term glycemic control in human diabetics. Using an automated nitroblue tetrazolium assay, fructosamine concentration was measured in serum from 24 healthy control cats and 3 groups of hospitalized cats: 32 euglycemic, 19 transiently hyperglycemic, and 12 diabetic cats. Fructosamine concentrations ranged from 2.1 - 3.8 mmol/L in clinically healthy cats; 1.1 - 3.5 mmol/L in euglycemic cats; 2.0 - 4.1 mmol/L in transiently hyperglycemic cats; and 3.4 to >6.0 mmol/L in diabetic cats. Values for with-in-run precision at 2 fructosamine concentrations (2.64 mmol/L and 6.13 mmol/L) were 1.5% and 1.3%, respectively. Between-run coefficient of variation was 3.8% at a fructosamine concentration of 1.85 mmol/L. The mean fructosamine concentration for the diabetic group differed significantly (P=0.0001) from the mean concentrations of the other 3 groups. Poorly regulated or newly diagnosed diabetic cats tended to have the highest fructosamine values, whereas well-regulated or over-regulated diabetic cats had values approaching the reference range. As a single test for differentiating nondiabetic cats from diabetic cats, fructosamine was very sensitive (92%) and specific (96%), with a positive predictive value of 85% and a negative predictive value of 98%. Serum fructosamine concentration shows promise as an inexpensive, adjunct diagnostic tool for differentiating transiently hyperglycemic cats from poorly controlled diabetic cats.