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Biomedical subjects

P H Brooks

Publications and source records attributed to P H Brooks.

At least 19 recordsLinked to original sources
PubMed2004

The effect of copper on the death rate of Salmonella typhimurium DT104:30 in food substrates acidified with organic acids.

AIMS: The objective of this study was to investigate the effect of copper ions on the survival of Salmonella typhimurium DT104:30 in acidified liquid food substrates. METHODS AND RESULTS: The decimal reduction time (Dvalue) of Salm. typhimurium DT104:30 was determined in acidified liquid pig feed (LPF) and skimmed milk (SM) containing a range of copper concentrations (0-50 ppm). As copper concentration increased, the death rate of Salm. typhimurium DT104:30 increased. In LPF acidified with 150 mmol l-1 lactic acid the presence of 50 ppm copper resulted in a 10-fold increase in the death rate. CONCLUSIONS: The presence of copper salts in acidic liquid food substrates significantly increases the death rate of Salm. typhimurium DT104:30. SIGNIFICANCE AND IMPACT OF THE STUDY: This finding could influence policy on levels of copper in pig feed.

Acetic Acid↗
PubMed2002

The effect of fermented liquid feeding on the faecal microbiology and colostrum quality of farrowing sows.

This study investigated the effects of fermented liquid feed (FLF) on the lactic acid bacteria (LAB):Coliform (L:C) ratio in the faeces of farrowing sows and the quality of sow colostrum. Eighteen multiparous sows were randomly allocated to one of three dietary treatments for approximately 2 weeks prior to farrowing and for 3 weeks after parturition. The three dietary treatments were dry pelleted feed (DPF), nonfermented liquid feed (NFLF), and fermented liquid feed (FLF). A rifampicin-resistant mutant of Lactobacillus plantarum was used to ferment liquid feed. Coliforms and lactic acid bacteria (LAB) in the faeces of farrowing sows and piglets were estimated by standard microbiological techniques. Intestinal epithelial cells (IEC-6) and blood lymphocytes were used to evaluate the mitogenic activity of colostral samples taken at parturition. Results demonstrated that while the LAB population was not significantly affected by dietary treatment, significant differences in coliform population were observed in the sow faecal samples taken 7 days after parturition. Faeces excreted from sows fed FLF had significantly (P < 0.001) lower numbers of coliforms than sows fed NFLF or DF. Piglets from sows fed FLF excreted faeces that were higher in LAB (7.7 vs. 7.3 log10 CFU g (-1); P < 0.01) and lower in coliforms (7.5 vs. 8.1 log10 CFU g (-1); P < 0.001) than faeces from the piglets of DF-fed dams. Colostrum from sows fed FLF had a significantly greater (P < 0.001) mitogenic activity on both intestinal cells (IEC-6) (79326 +/- 3069 CPM) and blood lymphocytes (1903 +/- 204 CPM) compared with colostrum from dry feed fed sows (53433 +/- 1568 and 1231 +/- 61.4 CPM, respectively). The combined effects of enhanced maternal/passive immunity and the reduction in the level of environmental contamination with faecal pathogens, achieved by FLF, may be important in achieving improved health status for both sows and piglets.

Animal Feed↗
PubMed2002

The effect of temperature on the growth and persistence of Salmonella in fermented liquid pig feed.

Two studies were conducted to investigate the effect of temperature on the fate of Salmonella enterica subsp. enterica serovar typhimurium DT104:30 in fermented liquid pig feed. These were (1) by co-inoculation of feed with S. typhimurium DT104:30 and Pediococcus pentosaceus, as the fermenting organism, and (2) by fermenting feed for 48, 72 or 96 h prior to inoculation with S. typhimurium DT104:30. In co-inoculated feed incubated at 20 degrees C, S. typhimurium DT104:30 persisted for at least 72 h. In contrast, in feed incubated at 30 degrees C, no S. typhimurium DT104:30 were detectable 48 h after inoculation. In prefermented feed, S. typhimurium DT104:30 died four to five times faster in feed maintained at 30 degrees C (D(value) 34-45 min) compared with feed maintained at 20 degrees C (D(value) 137-250 min). This was not entirely due to differences in lactic acid concentration as feed fermented for 72 or 96 h at 20 degrees C and feed fermented for 48 h at 30 degrees C contained similar concentrations of lactic acid (160-170 mM). Low numbers of S. typhimurium DT104:30 were still detectable in fermented feed 24 h after inoculation at 20 degrees C. In contrast, none were detectable 6-7 h after inoculation at 30 degrees C. The results of these studies indicate that it would be advisable for pig producers to control the temperature of liquid feed tanks to reduce the risk of Salmonella contamination.

Animal Feed↗
PubMed1998

Assessment of the injuries sustained by pregnant sows housed in groups using electronic feeders.

The incidence of injuries to pregnant sows kept in dynamic groups in a commercial herd was recorded over a period of 18 months. The sows were maintained in a solid-floored building with a straw-bedded lying area allowing 1.7 m2 per sow and fed by means of electronic feeders. Injuries on 12 possible areas of the body were assessed every week, and graded on the scale of 0 to 3 (maximum body score 36). The lesion scores sustained by the sows were very low, with a maximum of 19 and a median of 4. Lesions of the greatest severity constituted only 0.16 per cent of all the recorded injuries. The injuries were not distributed uniformly over the body, most being on the shoulders, flanks and hindquarters, with very few on the head or in the vulval region. The total injury score was related to parity, with sows in parities one, two and three sustaining more injuries than sows in later parities, and it was also related negatively to bodyweight. More agonistic interactions were observed between sows in the lying area and in the vicinity of the feeders than in the dunging area.

Aggression↗
PubMed1988

Supplementary biotin for sows: effect on claw integrity.

Eighty female pigs were fed, from 25 kg liveweight, either basal diets calculated to provide 32 micrograms available biotin/kg (control diet) or basal diets supplemented with 350 micrograms biotin/kg. Their claws were examined and lesions recorded at 170 days of age and when each of their first four litters was weaned. The incidence of horn 'defects' (superficial bruises, abrasions and cuts in the soft heel) remained at a low level throughout the trial. Neither the number of claws affected with lesions nor the number of lesions per sow differed between treatments at 170 days of age. Between 170 days of age and first weaning the incidence of hoof lesions increased greatly. At first weaning and for the remainder of the trial biotin supplemented sows had significantly fewer claw lesions per sow than controls (P less than 0.05 or greater). The predominant injuries to the foot were cracks which occurred mainly in two associated regions, the heel/toe junction and the heel, and the sidewall and adjacent white-line region of the toe. The differences in foot damage did not result in differences in culling rate. It was concluded that supplemention of the diet of breeding sows with biotin from an early stage of development made a significant contribution to the maintenance of their horn integrity.

Animals↗
PubMed1984

Water intake of weaned piglets from three to seven weeks old.

One hundred and two large white cross landrace piglets weaned at 21 (+/- 1) days old were randomly allocated to one of two commercial early weaning diets for a four week growth trial. The piglets were housed in groups of between six and 10. After initial moderate restriction the piglets were fed ad libitum. Food intakes and weight gains were recorded weekly. Water consumption of individual pens of piglets was recorded daily. Dietary treatment had no significant effect on mean daily feed intake, daily liveweight gain or food conversion ratio. The relationship between water and food intake, piglet weight and daily gain was examined using regression and multiple regression analyses. Water intake was related to all these parameters, with daily feed intake being the best single predictor of water intake. The relationship was described by the equation: water intake (litres/day) = 0.149 + 3.053 feed intake (kg/day).

Animal Feed↗
PubMed1984

Cognitive research in mental retardation.

Virtually all investigators currently conducting cognitive research in mental retardation address directly or indirectly the question of cognitive modifiability. Within that context we have dichotomized the research for discussion purposes into two classes. The first class includes research aimed at the development of an empirically based cognitive model of mental retardation. Investigators who do this work believe that strategies for cognitive modifiability will follow directly from a thorough understanding of the structures and processes that comprise the cognitive system. The second class of cognitive research in mental retardation is composed of studies on intervention. This research is focused on identification of cognitive deficiencies and subsequent attempts to alleviate these deficiencies. In this paper we have briefly provided examples of research from both classes chosen from ongoing research at the John F. Kennedy Center for Research on Education and Human Development.

Attention↗
PubMed1983

Supplementary biotin for sows: effect on reproductive characteristics.

Eighty female pigs were fed from 25 kg liveweight either basal diets calculated to provide 32 micrograms available biotin/kg (control diet) or basal diets supplemented with 350 micrograms biotin/kg. Reproductive performance was studied over four parities. Sows receiving supplementary biotin returned to oestrus 2.9 +/- 1.7 and conceived 6.1 +/- 1.4 days sooner than controls (P less than 0.05). Of those sows receiving supplementary biotin, more returned to oestrus and conceived within 10 days of weaning (83.2 per cent v 74.6 per cent and 80.6 per cent v 71.8 per cent respectively) and fewer were treated for anoestrus (7.3 per cent v 17.0 per cent) than those on the control diet. Supplementing diets increased the annual productivity of sows completing four parities by 1.42 +/- 1.02 pigs/sow/year (P less than 0.05) and increased the total weight of weaner produced/sow/year by 17.3 +/- 7.4 kg (P less than 0.05). It was concluded that the majority of commercial dietary formulations would require supplementation with biotin in order that sows may express their full reproductive potential.

Animal Feed↗
PubMed1977

Biotin-supplementation of diets; the incidence of foot lesions, and the reproductive performance of sows.

The effect of biotin supplementation of diets for breeding sows was investigated in a herd where the sows exhibited symptoms resembling those of experimentally induced biotin deficiency. Twenty sows received diets supplemented with 250 mcg D-biotin per kg in pregnancy and 150 mcg D-biotin per kg in lactation. Over a six month period the supplemented sows showed a 28 per cent reduction in the number of foot lesions recorded. Twenty-two control sows showed no reduction in foot lesions. Sows on the supplemented diets produced more piglets at birth than controls, but the differences were not significant. However, second parity supplemented sows did produce significantly more live pigs than controls (1-64 +/- 0-77, P less than 0-05). The weaning to remating interval was significantly reduced from 15-31 +/- 2-85 days in the controls to 6-23 +/- 2-85 days in the supplemented sows (P less than 0-05) and the percentage of sows exhibiting oestrus within seven days of weaning was increased from 56 per cent to 89 per cent.

Animals↗
PubMed1977

A plea for consideration of ecological validity in the experimental psychology of mental retardation: a guest editorial.

The point was raised that, despite considerable experimental effort, laboratory research concerning learning, memory, and cognition, more generally, has not produced a very remarkable increase in our understanding of retarded behavior. Our principal contention in this paper is that the experimental psychology of mental retardation, while basically seeking causal relations between theoretical constructs and retarded behavior, is suffering from some metatheoretical and methodological shortcomings. These include, basically, a prevalent failure to consider the ecological aspects of the phenomenon of mental retardation. Implications of ecological validity are important with respect to the basis upon which subjects are selected for experimentation, the rationale underlying manipulation of independent variables, the choice of dependent variables, and the definition of the boundaries that limit generalizations. Some suggestions were offered for the purpose of guiding experimental research toward more meaningful and socially relevant goals.

Humans↗
PubMed1977

Are we making a science of missing the point?

Our basic point of contention with House concerns the form we ultimately expect our sceintific explanations of retarded behavior to take. It is our view that mental retardation, which is basically a social phenomenon, can be meaningfully understood only to the extent that ecological validity and other related issues are assigned prominence in our theories and experiments.

Discrimination Learning↗