Sequential feeding can increase activity and improve gait score in meat-type chickens

This study investigated the short- and long-term effects of sequential feeding by alternating low-and high-lysine diets during the day on growth, gait score (GS), and behavior in broilers. From Days 2 to 12, 6 pens of 10 birds were assigned to control treatment and fed a standard normal lysine diet (NL) (ME = 3,250 kcal/kg, CP = 23%, Lys = 1.19%) and six pens of 10 birds were assigned to the sequential treatment and fed a low-lysine diet (LL) (Lys = 0.85%) for half of the day and NL for the other half of the day. From Days 13 to 21, all groups were fed NL, and from Days 21 to 42, they were fed a grower diet. Sequential (S) chicks were lighter than Control chicks at Days 13 (304 +/- 6 vs. 378 +/- 7 g) and 42 (2,588 +/- 31 vs. 2,714 +/- 10 g) and had better leg condition at Day 42 (mean GS = 1.6 +/- 0.1 vs. 2.1 +/- 0.1, P < or = 0.05). During a day of S feeding, S birds ate less and wasted more LL than NL. Sequential birds spent less time standing and more time lying idle when fed LL than when fed NL. Sequential birds spent more time eating than Control birds, and they gradually increased the number of pecks in the litter during a sequential feeding day. The results suggest a major effect of food composition on behavior. Sequential feeding could be a means of decreasing leg problems in broilers.

Early-age thermal conditioning reduces uncoupling protein messenger RNA expression in pectoral muscle of broiler chicks at seven days of age

Early-age thermal conditioning (TC) by exposing young chicks to 40 C for 24 h reduces body temperature (Tb) and has been showed by others to improve long-term resistance of broilers to heat stress. Uncoupling oxidative phosphorylation in pectoral muscle mitochondria might be related to heat production. Fertile eggs were hatched under video control, and 161 pedigree chicks froml2 sires and 22 dams were immediately allocated to two groups (T, a group composed of 81 chicks exposed to TC at 5 d of age, and N, a control group of 80 nonexposed chicks). Body weights and Tb were measured at 2 and 7 d of age. Five pairs (one N and one T) of full sib chicks from families that exhibited the largest difference of Tb variation from 2 to 7 d of age between the two treatments were chosen for pectoral muscle sampling. Avian uncoupling protein (avUCP) messenger RNA expression was measured by reverse transcript-PCR coupled to southern blot in the pectoral muscle of 7-d-old broiler chicks. At 7 d of age, there were no BW differences between treatments and Tb was significantly reduced by TC (-0.13 C on average). Heritability of Tb variation between 2 and 7 d was 0.38 +/- 0.20 (SE) for T chicks and 0.35 +/- 0.17 for N chicks without a significant genetic correlation between the two environments. Expression of avUCP mRNA was significantly (85%) lower in T chicks than in N chicks. Uncoupling protein mRNA expression in pectoral muscle and Tb are quickly adjusted in broiler chicks 24 h after early thermal conditioning.

Familial resemblance of bone mineral density between females 18 years and older and their mothers

Potential determinants of bone mass were investigated in a group of 70 young females (mean age 26.6 years), daughters of women studied in premenopause. Nutritional data, leisure physical activity level, lifestyle habits as well as familial similarities were assessed. The daughters' bone mineral density (BMD), measured by dual-energy absorptiometry, was significantly correlated with their body mass index (BMI) (r = 0.22), dietary vitamin D intake (r = 0.19) and their mothers' BMD (r = 0.44). Multiple regression analysis indicated that only the mothers' BMD remained an independent predictor of bone mass. Mother-daughter correlations were also observed for body weight (r = 0.24), height (r = 0.39), BMI (r = 0.29), dietary calcium intake (r = 0.20), and calcium (r = 0.20) or vitamin D (r = 0.25) intakes from dairy products. Hence, these observations support the evidence that mothers' BMD is the strongest predictor of bone mass of young women in their third decade.

Chicken leptin: properties and actions

Chicken leptin cDNA shows a high homology to mammalian homologous, with an expression localized in the liver and adipose tissue. It is noteworthy, that the hepatic expression is most likely associated with the primary role that this organ plays in lipogenic activity in avian species. As in mammals, chicken leptin expression is regulated by hormonal and nutritional status. This regulation is tissue-specific and with a high sensitivity in the liver compared to adipose tissue. The blood leptin levels are regulated by the nutritional state with high levels in the fed state compared to the fasted state. The recombinant chicken leptin markedly inhibits food intake as reported in mammals, suggesting the presence of an hypothalamic leptin receptor. The chicken leptin receptor has been identified and all functional motifs are highly conserved compared to mammalian homologous. Chicken leptin receptor is expressed in the hypothalamus but also in other tissues such as pancreas, where leptin inhibits insulin secretion and thus may have a key role in regulating nutrient utilization in this species.

Genome quality control: RIP (repeat-induced point mutation) comes to Podospora

RIP (repeat-induced point mutation) is a silencing process discovered in Neurospora crassa and so far clearly established only in this species as a currently occurring process. RIP acts premeiotically on duplicated sequences, resulting in C-G to T-A mutations, with a striking preference for CpA/TpG dinucleotides. In Podospora anserina, an RIP-like event was observed after several rounds of sexual reproduction in a strain with a 40 kb tandem duplication resulting from homologous integration of a cosmid in the mating-type region. The 9 kb sequenced show 106 C-G to T-A transitions, with 80% of the replaced cytosines located in CpA dinucleotides. This led to the alteration of at least six genes, two of which were unidentified. This RIP-like event extended to single-copy genes between the two members of the repeat. The overall data show that the silencing process is strikingly similar to a light form of RIP, unaccompanied by C-methylation. Interestingly, the N. crassa zeta-eta sequence, which acts as a potent de novo C-methylation RIP signal in this species, is weakly methylated when introduced into P. anserina. These results demonstrate that RIP, at least in light forms, can occur beyond N. crassa.

Revisiting speech interference in classrooms

A review of the effects of ambient noise and reverberation on speech intelligibility in classrooms has been completed because of the long-standing lack of agreement on preferred acoustical criteria for unconstrained speech accessibility and communication in educational facilities. An overwhelming body of evidence has been collected to suggest that noise levels in particular are usually far in excess of any reasonable prescription for optimal conditions for understanding speech in classrooms. Quite surprisingly, poor classroom acoustics seem to be the prevailing condition for both normally-hearing and hearing-impaired students with reported A-weighted ambient noise levels 4-37 dB above values currently agreed upon to provide optimal understanding. Revision of currently proposed room acoustic performance criteria to ensure speech accessibility for all students indicates the need for a guideline weighted for age and one for more vulnerable groups. For teens (12-year-olds and older) and young adults having normal speech processing in noise, ambient noise levels not exceeding 40 dBA are suggested as acceptable, and reverberation times of about 0.5 s are concluded to be optimum. Younger students, having normal speech processing in noise for their age, would require noise levels ranging from 39 dBA for 10-11-year-olds to only 28.5 dBA for 6-7-year-olds. By contrast, groups suspected of delayed speech processing in noise may require levels as low as only 21.5 dBA at age 6-7. As one would expect, these more vulnerable students would include the hearing-impaired in the course of language development and non-native listeners.

Performance of pureline broiler breeders fed two levels of vitamin E

Reported in this paper is an experiment designed to evaluate responses of two commercial broiler dam purelines (A and B) continuously fed 10 or 300 IU of vitamin E/kg from 168 to 441 d of age. Prior to Day 168, all pullets were fed diets containing 10 IU of vitamin E/kg. During the early laying period, percentage hen-day ovulations and percentage hen-day normal egg production were similar for both lines and diets. During the latter part of the laying cycle, there were differences between lines for these traits (A > B), as well as for BW and egg weight for which line differences were reversed (A < B). Also during this period, percentage hen-day ovulations and percentage hen-day normal egg production differed between diets (300 > 10 IU/kg). These differences between diets were consistent with the greater number of females that entered lay and higher hen-housed egg production of the 300- than 10-IU/kg group. Although during the laying cycle all females received a fixed amount of feed, BW gains were greater for Line B than A and for the 300- than the 10-IU/kg level of vitamin E. Heterophil (H):lymphocyte (L) ratios, percentage livability, and relative asymmetries of shank length and diameter were similar among groups. Pullets from Line B and those fed the higher level of vitamin E exhibited more fear than their counterparts. Head shaking did not differ between vitamin E levels; however, there was a line-by-time of day interaction for this behavior. The 30-fold difference in dietary vitamin E was reflected by a 15-fold difference in plasma vitamin E levels in both lines. For vitamin E level in the yolk, however, there was a line-by-diet interaction. The interaction resulted from no difference between lines at the 10 IU/kg level and differences of 10- and 6+-fold in Lines B and A at the 300 IU/ kg level, respectively. Overall, responses to continuous feeding of vitamin E at these levels were influenced by genetic stock, age, duration of feeding, and measurement criteria.

Familial resemblance of bone mineral density between females 18 years and older and their mothers

Potential determinants of bone mass were investigated in a group of 70 young females (mean age 26.6 years), daughters of women studied in premenopause. Nutritional data, leisure physical activity level, lifestyle habits as well as familial similarities were assessed. The daughters' bone mineral density (BMD), measured by dual-energy absorptiometry, was significantly correlated with their body mass index (BMI) (r = 0.22), dietary vitamin D intake (r = 0.19) and their mothers' BMD (r = 0.44). Multiple regression analysis indicated that only the mothers' BMD remained an independent predictor of bone mass. Mother-daughter correlations were also observed for body weight (r = 0.24), height (r = 0.39), BMI (r = 0.29), dietary calcium intake (r = 0.20), and calcium (r = 0.20) or vitamin D (r = 0.25) intakes from dairy products. Hence, these observations support the evidence that mothers' BMD is the strongest predictor of bone mass of young women in their third decade.

eEF1A Controls ascospore differentiation through elevated accuracy, but controls longevity and fruiting body formation through another mechanism in Podospora anserina

Antisuppressor mutations in the eEF1A gene of Podospora anserina were previously shown to impair ascospore formation, to drastically increase life span, and to permit the development of the Crippled Growth degenerative process. Here, we show that eEF1A controls ascospore formation through accuracy level maintenance. Examination of antisuppressor mutant perithecia reveals two main cytological defects, mislocalization of spindle and nuclei and nuclear death. Antisuppression levels are shown to be highly dependent upon both the mutation site and the suppressor used, precluding any correlation between antisuppression efficiency and severity of the sporulation impairment. Nevertheless, severity of ascospore differentiation defect is correlated with resistance to paromomycin. We also show that eEF1A controls fruiting body formation and longevity through a mechanism(s) different from accuracy control. In vivo, GFP tagging of the protein in a way that partly retains its function confirmed earlier cytological observation; i.e., this factor is mainly diffuse within the cytosol, but may transiently accumulate within nuclei or in defined regions of the cytoplasm. These data emphasize the fact that the translation apparatus exerts a global regulatory control over cell physiology and that eEF1A is one of the key factors involved in this monitoring.

Akt activation preserves cardiac function and prevents injury after transient cardiac ischemia in vivo

BACKGROUND

The serine-threonine kinase Akt is activated by several ligand-receptor systems previously shown to be cardioprotective. Akt activation reduces cardiomyocyte apoptosis in models of transient ischemia. Its role in cardiac dysfunction or infarction, however, remains unclear.

METHODS AND RESULTS

We examined the effects of a constitutively active Akt mutant (myr-Akt) in a rat model of cardiac ischemia-reperfusion injury. In vivo gene transfer of myr-Akt reduced infarct size by 64% and the number of apoptotic cells by 84% (P<0.005 for each). Ischemia-reperfusion injury decreased regional cardiac wall thickening as well as the maximal rate of left ventricular pressure rise and fall (+dP/dt and -dP/dt). Akt activation restored regional wall thickening and +dP/dt and -dP/dt to levels seen in sham-operated rats. To better understand this benefit, we examined the effects of myr-Akt on hypoxic cardiomyocyte dysfunction in vitro. myr-Akt prevented hypoxia-induced abnormalities in cardiomyocyte calcium transients and shortening. Akt activation also enhanced sarcolemmal expression of Glut-4 in vivo and increased glucose uptake in vitro to the level seen with insulin treatment.

CONCLUSIONS

Akt activation exerts a powerful cardioprotective effect after transient ischemia that probably reflects its ability to both inhibit cardiomyocyte death and improve function of surviving cardiomyocytes. Akt may represent an important nodal target for therapy in ischemic and other heart disease.

Do broiler chicks have a cognitive representation of food quality? Appetitive, behavioural and ingestive responses to a change in diet quality

It has been observed that when a new diet formulation, or a new batch of the same diet formulation, is presented to poultry, there is a transitory suppression of feeding. It appears that the birds do not recognise the food as being edible, or classify it as being 'unknown'. In order to understand more about food recognition and rejection, the aim of this experiment was to determine whether cognitive processes are involved. Sixteen groups of four broiler chicks were used, and were fed a low quality diet in their home pens. The groups of chicks were trained to run a winding maze to gain access to a high quality diet in a test trough for 15min per day. When training was completed, the feed in the test trough for eight of the groups was changed to that which they received in the home pen, while the other eight groups received no change as a control. Time to traverse the runway did not show an immediate decrease on the day after the change (P>0.05) as would be expected if the birds used a cognitive comparison to determine speed of approach to the test trough. However, the experimental groups were significantly slower compared to the control groups after 4 days (P<0.05). The behaviour observed on the day of the change was indicative of frustration with more scratching and hurried movements shown (P<0.05), and less pecking at feed (P<0.01). Food consumption was lower for experimental groups compared to control groups on all days from the day of change onward (P<0.001). It was concluded that although there was no definitive evidence for the presence of a cognitive representation of food, this may have been due in part to the testing of groups of birds rather than individuals, and the way in which food quality is perceived. The occurrence of behaviours indicative of frustration suggest that a cognitive expectation may have been present.

Concept, development, administration, and analysis of a certifying examination in echocardiography for physicians

In 1993, the American Society of Echocardiography appointed a committee to develop an objective examination in echocardiography. In 1995, a pilot of this examination was administered, with operational examinations offered each year from 1996 to 1999. This report describes the development of the examination, including its underlying philosophy, the test itself, and the scoring process, and includes results from the first 4 examinations. To date, 1266 physicians have taken the examination, and roughly 60% of those have passed. The number of echocardiograms performed or interpreted each week had the largest effect on examination scores; the effects of both the amount of training and the practice discipline were small but significant. The evolution of the original committee and new directions for the testing organization are also discussed.

Early age thermal conditioning and a dual feeding program for male broilers challenged by heat stress

The effects of early age thermal conditioning (TC) and dual feeding on responses of male broilers to a thermal challenge at 34 d of age are reported. Three hundred chicks were randomly divided into two equal groups. One group was exposed to thermal conditioning (38 C, 42% relative humidity for 24 h) at the age of 5 d, and the other group was not exposed. From 11 to 41 d of age, temperature was diurnally cyclic: 26 C (1600 to 0900 h) and 30 C (0900 to 1600 h). From Day 19, a factorial (2 x 2, TC x diet) experiment was conducted using eight pens of six broilers per treatment. Diets were control diet and dual feeding of a high protein fraction (1600 to 0900 h) and an energy-rich fraction (0900 to 1600 h). Growth and feed efficiency were slightly enhanced (+4%) by thermal conditioning and slightly reduced (-4%) by dual feeding. Mortality during thermal challenge was reduced by both factors. [In not conditioned chicks (N), 31 fed a control grower diet (NG) and 12 on a dual feeding program (NDF) died; in thermal conditioned chicks (T), 18 fed a control grower diet (TG) and 11 on a dual feeding program (TDF) died.] Before the thermal challenge period, body temperature (Tb) was consistently reduced in T. During the thermal challenge period, Tb was reduced by thermal conditioning and dual feeding. Measured at the age of 32 d, Tb gave an estimation of the ability of the chickens to cope with heat stress 2 d later. Pectoral mass was increased in TG, whereas the liver and the gizzard were significantly heavier in TDF and NDF. These results suggest that thermal conditioning at 5 d of age induces a consistent metabolic change in broiler males. The dual feeding program might have induced transitory effects on heat production during the heat stress.

Antibody responses of hens fed vitamin E and passively acquired antibodies of their chicks

Antibody responses of hens and their progeny were studied in commercial broiler nuclear lines. Starting at 168 days of age, individually housed pullets from lines A and B were fed a 16% crude protein and 2752 kcal metabolizable energy/kg mash diet supplemented with either 10 or 300 IU/kg of vitamin E fed as dl-alpha-tocopherol acetate. Fifty-eight days later (226 days of age), 12 hens per line-vitamin E subclass were inoculated i.v. with 0.1 ml of a 2.5% suspension of sheep red blood cells (SRBC). Plasma antibody titers were measured 6, 20, 40, 54, 70, and 88 days after inoculation. Hens from both lines were artificially mated to males from line C, and progeny from eggs collected 9-15, 25-30, and 65-70 days after inoculation were tested for antibodies to SRBC. Hens were reinoculated i.v. with 0.1 ml of 0.25% SRBC 88 days after the first inoculation, and their antibody levels were measured 3, 6, and 20 days later. Eggs laid 10-13 days after reinoculation were incubated, and antibody titers of chicks were measured at hatch. Antibody response of hens to an initial inoculation of SRBC was line-diet-time after inoculation specific. In line A, titers were greater for hens fed the lower than the higher vitamin E diet, whereas diet had no effect on the antibody levels in line B. Line effects (A > B) were observed on days 6 and 20 after inoculation but not thereafter. After the second inoculation, dietary vitamin E level had no effect on antibody levels of hens within lines, whereas a between-line difference (A > B) was observed for the lower but not the higher level of dietary vitamin E. Although there was no difference between diets for antibody transferred to progeny by line B, there was a difference (lower > higher) for line A. After reinoculation of their dams, antibody titers of chicks from line A, but not line B, reached levels similar to those after the first inoculation. Antibody levels were higher for chicks at hatch than in 16-day embryos or 10 days posthatch. The results of this research suggest genetic variation in response to immune stimulation by dietary vitamin E.

Time structure of behavioral patterns related to feed pecking in chicks

Nonrandom time patterns of pecking acts by 16 chicks were detected using the software Theme during three videotaped pecking sessions (M, C, and A). At 15 days of age pecking session, M (mash) was recorded when chicks ate a mash diet. Pecking session C (change) at 16 or 17 days of age was recorded immediately after the change of the diet to pellets presented either as regular cylinders (P) to eight chicks, or as semiovoid (Po) to eight other chicks. Pecking session A (adapted) was recorded 5 or 6 days after adaptation to P and Po. Successful (consumatory) pecks were 72%, 52%, and 61% of all pecks for sessions M, C, and A, respectively. The head of the chicks remained in a steady position between two consecutive pecks for a longer period during C (65% of the time) than M and A (54%). During C, the pecking rate was less for P (0.54 pecks/s) than for Po (0.79 pecks/s). Two consistent time patterns involving four acts frequently observed were: head rotation (or exploratory peck)-->head in steady position-->consumatory peck-->head in steady position with jaw movements. Time intervals within a pattern were stable throughout sessions. However, the proportion of synchronized (included in a pattern) vs. nonsynchronized (not included in a pattern) acts decreased immediately after the change of feed form (session C). These results suggest that pecking at feed is composed of two distinct sets of acts: consistently organized patterns little affected by the form of the pecked particles and nonsynchronized acts that may be involved in sensory information.

Subacute but not acute generation of nitric oxide in focal cerebral ischemia

BACKGROUND AND PURPOSE

Excessive release of nitric oxide (NO) has been implicated in the pathophysiology of neurodegeneration in ischemic stroke. We compared intracerebral release of indicators of NO generation at the acute and subacute stages of transient focal cerebral ischemia.

METHODS

In vivo microdialysis in the rat striatum was performed at the acute (first hours) and subacute (after 24 or 48 hours) stages of cerebral ischemia or sham operation to monitor intracerebral release of the stable NO metabolites nitrite and nitrate.

RESULTS

Whereas only a nonsignificant trend toward increased release of these NO metabolites was evidenced in acute cerebral ischemia, a significant NO generation was observed subacutely, 48 hours after induction of cerebral ischemia. Aminoguanidine, a selective inhibitor of inducible NO synthase, suppressed this delayed release of nitrite and nitrate.

CONCLUSIONS

Whereas these observations do not support a major NO generation in acute cerebral ischemia, they indicate an inducible NO synthase-dependent NO generation predominantly at the subacute phase of ischemic neurodegeneration. Therefore, NO generation may play a pathophysiological role in delayed ischemic neurodegeneration.

Subacute NO generation induced by Alzheimer's beta-amyloid in the living brain: reversal by inhibition of the inducible NO synthase

Glial activation contiguous to deposits of amyloid peptide (Abeta) is a characteristic feature in Alzheimer's disease. We performed complementary in vitro and in vivo experiments to study the extent, kinetics, and mechanisms of microglial generation of nitric oxide (NO) induced by challenge with Abeta. We showed that Abeta fibrils dose-dependently induced a marked release of stable metabolites of NO in vivo that was strikingly similar regarding extent and temporal profile to the one in the parallel designed microglial cell culture experiments. However, costimulation with interferon gamma, which was a prerequisite for Abeta-induced NO generation in vitro, was not required in vivo, demonstrating that factors are present in the living brain that activate glial cells synergistically with Abeta. Therefore, in Alzheimer's disease, deposits of Abeta fibrils alone may be sufficient to induce a chronic release of neurotoxic microglial products, explaining the progressive neurodegeneration associated with this disease. Our observation that systemic administration of selective iNOS inhibitors abolishes Abeta-induced NO generation in vivo may have implications for therapy of Alzheimer's disease.

Biological activities of recombinant chicken leptin C4S analog compared with unmodified leptins

The chicken leptin sequence, in contrast to mammalian leptins, contains an unpaired Cys at position 3 of the original cDNA (AF012727). The presence of an extra Cys may confer a different structure and affect the leptin's biological activity. To address this, we studied the effects of wild-type and mutated (C4S) chicken leptins in vitro and in vivo and compared them with mammalian leptin prepared from ovine leptin cDNA. The prokaryotic expression vector pMON, encoding full-size A(-1) chicken leptin (AF012727), was mutated using a mutagenesis kit, yielding the C4S analog. Escherichia coli cells transformed with this vector overexpressed large amounts of chicken leptin C4S upon induction with nalidixic acid. The expressed protein, found in the inclusion bodies, was refolded and purified to homogeneity on a Q-Sepharose column, yielding three electrophoretically pure fractions, eluted from the column by 100, 125, and 150 mM NaCl, respectively. All three fractions showed a single band of the expected molecular mass (16 kDa) and were composed of >95% monomeric protein. Proper refolding was evidenced by comparing the circular dichroism spectrum of the analog with spectra of nonmutated chicken and ovine leptins. The biological activity of the C4S analog was evidenced by its ability to stimulate proliferation of leptin-sensitive BAF/3 cells transfected with a long form of human leptin receptor construct similar to its nonmutated counterpart, indicating that Cys4 plays no role in leptin activity. The in vitro activity of both wild-type and mutated chicken leptins was approximately 10-fold lower than that of ovine leptin. After intravenous or intraperitoneal injections, C4S analog and the nonmutated chicken and ovine leptins all lowered the food intake of starved 9-day-old broiler or 5-wk-old layer male chickens by 11-34%. Monitoring food behavior revealed that the attenuated food intake resulted not from a decreased number of approaches to the feeders but from a decrease in the average time spent eating during each approach.

Maintenance and integrity of the mitochondrial genome: a plethora of nuclear genes in the budding yeast

Instability of the mitochondrial genome (mtDNA) is a general problem from yeasts to humans. However, its genetic control is not well documented except in the yeast Saccharomyces cerevisiae. From the discovery, 50 years ago, of the petite mutants by Ephrussi and his coworkers, it has been shown that more than 100 nuclear genes directly or indirectly influence the fate of the rho(+) mtDNA. It is not surprising that mutations in genes involved in mtDNA metabolism (replication, repair, and recombination) can cause a complete loss of mtDNA (rho(0) petites) and/or lead to truncated forms (rho(-)) of this genome. However, most loss-of-function mutations which increase yeast mtDNA instability act indirectly: they lie in genes controlling functions as diverse as mitochondrial translation, ATP synthase, iron homeostasis, fatty acid metabolism, mitochondrial morphology, and so on. In a few cases it has been shown that gene overexpression increases the levels of petite mutants. Mutations in other genes are lethal in the absence of a functional mtDNA and thus convert this petite-positive yeast into a petite-negative form: petite cells cannot be recovered in these genetic contexts. Most of the data are explained if one assumes that the maintenance of the rho(+) genome depends on a centromere-like structure dispensable for the maintenance of rho(-) mtDNA and/or the function of mitochondrially encoded ATP synthase subunits, especially ATP6. In fact, the real challenge for the next 50 years will be to assemble the pieces of this puzzle by using yeast and to use complementary models, especially in strict aerobes.

ami1, an orthologue of the Aspergillus nidulans apsA gene, is involved in nuclear migration events throughout the life cycle of Podospora anserina

The Podospora anserina ami1-1 mutant was identified as a male-sterile strain. Microconidia (which act as male gametes) form, but are anucleate. Paraphysae from the perithecium beaks are also anucleate when ami1-1 is used as the female partner in a cross. Furthermore, in crosses heterozygous for ami1-1, some crozier cells are uninucleate rather than binucleate. In addition to these nuclear migration defects, which occur at the transition between syncytial and cellular states, ami1-1 causes abnormal distribution of the nuclei in both mycelial filaments and asci. Finally, an ami1-1 strain bearing information for both mating types is unable to self-fertilize. The ami1 gene is an orthologue of the Aspergillus nidulans apsA gene, which controls nuclear positioning in filaments and during conidiogenesis (at the syncytial/cellular transition). The ApsA and AMI1 proteins display 42% identity and share structural features. The apsA gene complements some ami1-1 defects: it increases the percentage of nucleate microconidia and restores self-fertility in an ami1-1 mat+ (mat-) strain. The latter effect is puzzling, since in apsA null mutants sexual reproduction is quite normal. The functional differences between the two genes are discussed with respect to their possible history in these two fungi, which are very distant in terms of evolution.

Vitamin E and immune responses of broiler pureline chickens

Immunological responses of cockerels fed diets containing either 10 or 300 mg/kg of vitamin E were measured in three commercial broiler nuclear lines designated as A, B, and C. All cockerels were fed the 10 mg/kg diet to 91 d of age, at which time half were continued on that diet and the other half were fed a diet supplemented to contain 300 mg/kg of vitamin E. Sixteen days after feeding the diets, cutaneous basophil hypersensitivity (CBH), which is an in vivo, cell-mediated immune response, was determined as the increase in toe-web skin thickness 24 h after an injection with phytohemagglutinin-P (PHA-P). Twenty-two days after feeding the diets, heterophils and lymphocytes were enumerated. At this time cockerels were also inoculated intravenously with 0.1 mL of 0.25% SRBC. The injection with SRBC was repeated 27 d later. Six and 20 d after each injection, antibody titers were determined. Mercaptoethanol-resistant (IgG) and mercaptoethanol-sensitive (IgM) antibodies were also measured in the secondary titers. The ratio of heterophils to lymphocytes increased, and CBH response was depressed by feeding the higher vitamin E diet. For cockerels of Lines A and B, the higher level of vitamin E maintained primary and secondary SRBC antibody levels, whereas for Line C, levels were depressed. The effect of the higher vitamin E diet on IgG and IgM was also stock-dependent. The enhanced heterophil:lymphocyte ratio from feeding vitamin E suggests an improved phagocytic ability of the immune system. Relative asymmetries for toe-web skin thickness and shank length were similar for the three lines.

A simple method for testing odor detection and discrimination in chicks

A simple procedure for testing newly hatched chicks' responses to olfactory stimuli is described. Chicks that were hand held under a heatlamp became inactive and closed their eyes (as if asleep) within 2 min. Sleeping chicks displayed overt behavioral responses to an odorized q-tip (head shaking, beak clapping) that were not observed in awake chicks. Sleeping latencies were shorter for 1-day-old chicks that had been food deprived prior to testing than for chicks that had ad lib access to food and water. When airborne odors were presented by squeezing a soft plastic odor bottle near the beak, sleeping chicks' reactions to mint were of a greater magnitude than their responses to lavender or orange scents. Nonetheless, all three odors elicited more pronounced behavioral responses than did the water control stimulus. This method allows rapid testing of individual chicks for odor detection and discrimination.

Regulation of cardiac hypertrophy in vivo by the stress-activated protein kinases/c-Jun NH(2)-terminal kinases

Cardiac hypertrophy often presages the development of heart failure. Numerous cytosolic signaling pathways have been implicated in the hypertrophic response in cardiomyocytes in culture, but their roles in the hypertrophic response to physiologically relevant stimuli in vivo is unclear. We previously reported that adenovirus-mediated gene transfer of SEK-1(KR), a dominant inhibitory mutant of the immediate upstream activator of the stress-activated protein kinases (SAPKs), abrogates the hypertrophic response of neonatal rat cardiomyocytes to endothelin-1 in culture. We now report that gene transfer of SEK-1(KR) to the adult rat heart blocks SAPK activation by pressure overload, demonstrating that the activity of cytosolic signaling pathways can be inhibited by gene transfer of loss-of-function mutants in vivo. Furthermore, gene transfer of SEK-1(KR) inhibited pressure overload-induced cardiac hypertrophy, as determined by echocardiography and several postmortem measures including left ventricular (LV) wall thickness, the ratio of LV weight to body weight, cardiomyocyte diameter, and inhibition of atrial natriuretic factor expression. Our data suggest that the SAPKs are critical regulators of cardiac hypertrophy in vivo, and therefore may serve as novel drug targets in the treatment of hypertrophy and heart failure.

Oral immunisation of swine with a classical swine fever vaccine (Chinese strain) and transmission studies in rabbits and sheep

Seven experiments including a total of 47 pigs, 11 wild boars, 26 rabbits, 10 hares and 16 sheep were carried out to assess the efficacy, safety and transmission of the Chinese vaccine strain of the classical swine fever virus (CSFV) administrated by the oral route. Within 3 weeks after oral vaccination, a clear seroconversion occurred in the pigs. Six weeks after vaccination, vaccinated pigs were fully protected against a virulent challenge. The C-strain was not isolated from tonsils, spleen, lymph nodes, thymus, saliva, urine and faeces of pigs within 4 days after oral vaccination. In one experiment, susceptible pigs were placed in direct contact with vaccinated pigs. None of these contact-exposed pigs became serologically positive for CSFV antibodies. It is concluded that the C-strain induces protection in pigs when administrated by the oral route and is not shed by vaccinated pigs. Serum anti-CSFV antibodies developed in seven out of eight wild boars vaccinated by the oral route. No vaccine virus was detected in the spleen and tonsils of these animals. The results in wild boar were in accordance with those obtained in domestic pigs. Sheep did not show any clinical signs after oral vaccination while rabbits had moderate hyperthermia and growth retardation. No clinical response to oral immunisation in hares was detected. At the end of the experiment, no sheep had detectable serum antibodies against CSFV, whereas a few vaccinated rabbits and hares became seropositive. None of the contact-exposed rabbits and hares seroconverted. These data indicate that the C-strain is safe for sheep and as expected, moderately or not pathogenic for rabbits and hares. These efficacy and safety studies on oral vaccination with the C-strain under experimental conditions provide essential information for further studies in wild boars under experimental and field conditions, including assays with baits to control a CSF epidemic.

Speech audiometry in noise-exposed workers: the SRT-PTA relationship revisited

The speech recognition threshold (SRT) is believed to be related primarily to the pure-tone average (PTA) and the steepness of the hearing loss. However, there are indications that it may also be influenced by perceptual or cognitive-linguistic factors, or both, such as meaningfulness of the speech stimuli. The purpose of the present study was to ascertain the correspondence between SRT and PTA in noise-exposed workers with various degrees of speech recognition threshold shift in noise. To this end, a total of 807 SRTs and PTAs collected from fluent speakers of Quebec French noise-exposed workers were compared. Measurements of context effects on speech recognition were taken based on a general hypothesis that they should be facilitating phoneme or word restoration in conditions of high stimulus uncertainty as present in SRT assessment, thus acting to confound the SRT PTA relationship. Using principal components analysis, we found a significant effect not only of low-frequency hearing sensitivity but language context effects on SRT. After a correction was introduced to partial out these linguistic context effects, correlations between SRT and PTA increased but they were lower than predicted. In a related treatment analysis, we found a large number of observations (230 out of 807) where SRTs were more sensitive than PTAs by a factor of 8 to 16 dB. This was the case even though correlations between the two measurements were within the range commonly advocated in the field of clinical audiology (0.85-0.95). This was interpreted as a sign of phonological and lexical context effects on the speech recognition task actually used by individual subjects to facilitate speech understanding, to the point perhaps of making it as simple as the detection of pure tones.

Effects of early odor exposure in domestic chicks

The effects of odor exposure during the last 2 days of incubation and immediately after hatching on subsequent responses by chicks to that same scent were assessed. When tested with an orange-treated and an unscented container, chicks that had been previously exposed to orange odor more rapidly approached both containers than did control chicks and spent more time near them. In both conditions, chicks spent significantly more time near the unscented container than the one treated with orange. In a second experiment, chicks previously exposed to orange odor and control chicks did not differ in their rates of locomotor activity or latency to approach stimulus containers when orange odor was not present. Chicks become familiar with specific odors as a function of early exposure. Differences between the behavior of exposed and naive chicks in the presence of orange odor may reflect neophobic responses by the controls.

Self-selection of dietary protein and energy by broilers grown under a tropical climate: adaptation when exposed to choice feeding at different ages

Three hundred broiler chicks (Hubbard) of both sexes were assigned to five feeding treatments: T0 received a complete diet (control), T1 was a choice feeding system with simultaneous access to an energy-rich feed (ground corn) and a protein concentrate (43.7% CP), and T2, T3, and T4 were introduced to choice feeding after 1, 3, and 5 wk, respectively, of consuming the complete diet. At 1-d-old, T1 chicks showed a marked preference for corn, with only 21.4% of their intake being the protein concentrate diet. Intake of the concentrate progressively increased to 40 to 45% after 3 d of adaptation, resulting in diets with 22.5 to 24.3% CP. When broilers fed the complete diet for 1 to 5 wk (T2, T3, T4) were changed to choice feeding, on the 1st d, their feed choice intake was similar to that of T1 chicks at the same age. Visual observation and tactile assessment of the feed particles during the initial period allowed the chicks to quickly evaluate the new feeds and to adapt their feeding behavior. Although total feed intake to 6 wk of age was not significantly affected by the feeding treatments, broilers on choice feeding selected diets with a lower percentage of CP and had lower live body weights at 6 wk than those fed the complete diet (T0).

Escape from Premature Death Due to Nuclear Mutations in Podospora anserina: Repeal versus Respite

Premature death has been defined as a growth stoppage linked to the accumulation of specific deletions of the mitochondrial genome (mtDNA) in Podospora anserina. This occurs only in strains carrying the AS1-4 mutation which lies in a gene encoding a cytosolic ribosomal protein. Here we describe the isolation and genetic characterization of 10 nuclear mutations which either delay the appearance of this syndrome (respite from premature death) or cause a switch to the classical senescence process (repeal of premature death). These mutations lie in at least six genes. Some cause defects at the levels of ascospore germination, growth rates, and/or sensitivity toward inhibitors of protein syntheses. All modify the onset of senescence in wild-type (AS1+) strains. The role played by these genes is discussed with respect to the control of diseases due to mtDNA rearrangements in filamentous fungi. Copyright 1998 Academic Press.

Cholecystokinin receptors mediate the development of a preference for the mother by newly born lambs

The aim of this study was to investigate the effect of selective cholecystokinin (CCK) antagonists on the development of a preference for the mother by newly born lambs. At birth lambs received an injection of the CCK-A antagonist devazepide (0.01 or 0.1 mg/kg), the CCK-B antagonist PD135158 (0.01 or 0.1 mg/kg), or saline for the controls (1 ml/kg). No major side effects were observed in the first 4 postnatal hours except that lambs receiving PD135158 displayed more exploratory behavior towards the maternal body than lambs from the other groups. When tested in a 2-choice test situation at 24 hr of age, lambs treated with PD135158 or saline spent significantly more time near their dams than near the alien ewes, whereas lambs treated with devazepide did not show any discrimination. The effect of devazepide persisted at 48 hr of age. The use of a CCK-A antagonist, but not a CCK-B antagonist, was concluded to prevent the formation of a preferential relationship between the lamb and its mother, most probably by impairing neonatal learning.

A homologue of the yeast SHE4 gene is essential for the transition between the syncytial and cellular stages during sexual reproduction of the fungus Podospora anserina

The Podospora anserina cro1 gene was identified as a gene required for sexual sporulation. Crosses homozygous for the cro1-1 mutation yield fruiting bodies which produce few asci due to the formation of giant plurinucleate cells instead of dikaryotic cells after fertilization. This defect does not impair karyogamy, but meioses of the resultant polyploid nuclei are most often abortive. Cytological studies suggest that the primary defect of the mutant is its inability to form septa between the daughter nuclei after each mitosis, a step specific for normal dikaryotic cell divisions. The cro1-1 mutant would thus be unable to leave the syncytial vegetative state while abiding by the meiotic programme. cro1-1 also shows defects in ascospore germination and growth rate. GFP-tagging of the CRO1 protein reveals that it is a cytosolic protein mainly expressed at the beginning of the dikaryotic stage and at the time of ascospore maturation. The CRO1 protein exhibits significant similarity to the SHE4 protein, which is required for asymmetric mating-type switching in budding yeast cells. Thus, a gene involved in asymmetric cell divisions in a unicellular organism plays a key role at the transition between the syncytial (vegetative) state and the cellular (sexual) state in a filamentous fungus.

Diet-induced thermogenesis in cockerels is modulated by genetic selection for high or low residual feed intake

Energy balance of adult cockerels genetically selected for high (R+) or low (R-) residual feed consumption was investigated by using indirect calorimetry. Although no between-line difference was found in digestion of ingested energy, the true metabolizable energy (ME) intake was 40% greater in R+ than in R- birds. Basal heat production (HP) did not significantly differ between genotypes. Diet-induced thermogenesis (DIT) was significantly enhanced in R+ compared with R- birds, i.e., +84% when expressed as the difference in kilojoules of heat production determined in feed-deprived and fed cockerels, +31% when calculated as a percentage of ME intake (P < 0.01). The difference in DIT calculated from the regression between HP and physical activity explained 75% of the difference in HP; the remaining 25% could be explained by activity-related HP. The results cannot be explained by differences in the plasma concentration of circulating thyroid hormones: plasma thyroxine concentration did not differ between genotypes, whereas plasma triiodothyronine concentration was lower in feed-deprived R+ than in R- birds and indistinguishable in fed birds of the two lines. Heat production, however, was higher in the R+ line. Propranolol decreased HP only in the R+ line, suggesting a beta-adrenergic control of DIT at least in cockerels of this line. Plasma triglyceride concentration was lower in the R+ than in the R- line in fed cockerels, and plasma nonesterified fatty acid concentration was higher in the R+ than in the R- line in feed-deprived cockerels. These results are consistent with the leanness of the R+ compared with the R- line. The R+ and R- lines constitute an original model of diet-induced thermogenesis (DIT), a process that is under genetic control of appetite and allows R+ birds to balance all of their excessive energy intake without any adipose tissue storage.

Cholecystokinin receptors mediate the development of a preference for the mother by newly born lambs

The aim of this study was to investigate the effect of selective cholecystokinin (CCK) antagonists on the development of a preference for the mother by newly born lambs. At birth lambs received an injection of the CCK-A antagonist devazepide (0.01 or 0.1 mg/kg), the CCK-B antagonist PD135158 (0.01 or 0.1 mg/kg), or saline for the controls (1 ml/kg). No major side effects were observed in the first 4 postnatal hours except that lambs receiving PD135158 displayed more exploratory behavior towards the maternal body than lambs from the other groups. When tested in a 2-choice test situation at 24 hr of age, lambs treated with PD135158 or saline spent significantly more time near their dams than near the alien ewes, whereas lambs treated with devazepide did not show any discrimination. The effect of devazepide persisted at 48 hr of age. The use of a CCK-A antagonist, but not a CCK-B antagonist, was concluded to prevent the formation of a preferential relationship between the lamb and its mother, most probably by impairing neonatal learning.

Mating types and sexual development in filamentous ascomycetes

The progress made in the molecular characterization of the mating types in several filamentous ascomycetes has allowed us to better understand their role in sexual development and has brought to light interesting biological problems. The mating types of Neurospora crassa, Podospora anserina, and Cochliobolus heterostrophus consist of unrelated and unique sequences containing one or several genes with multiple functions, related to sexuality or not, such as vegetative incompatibility in N. crassa. The presence of putative DNA binding domains in the proteins encoded by the mating-type (mat) genes suggests that they may be transcriptional factors. The mat genes play a role in cell-cell recognition at fertilization, probably by activating the genes responsible for the hormonal signal whose occurrence was previously demonstrated by physiological experiments. They also control recognition between nuclei at a later stage, when reproductive nuclei of each mating type which have divided in the common cytoplasm pair within the ascogenous hyphae. How self is distinguished from nonself at the nuclear level is not known. The finding that homothallic species, able to mate in the absence of a partner, contain both mating types in the same haploid genome has raised more issues than it has resolved. The instability of the mating type, in particular in Sclerotinia trifolorium and Botrytinia fuckeliana, is also unexplained. This diversity of mating systems, still more apparent if the yeasts and the basidiomycetes are taken into account, clearly shows that no single species can serve as a universal mating-type model.

Mutations in genes encoding the mitochondrial outer membrane proteins Tom70 and Mdm10 of Podospora anserina modify the spectrum of mitochondrial DNA rearrangements associated with cellular death

Tom70 and Mdm10 are mitochondrial outer membrane proteins. Tom70 is implicated in the import of proteins from the cytosol into the mitochondria in Saccharomyces cerevisiae and Neurospora crassa. Mdm10 is involved in the morphology and distribution of mitochondria in S. cerevisiae. Here we report on the characterization of the genes encoding these proteins in the filamentous fungus Podospora anserina. The two genes were previously genetically identified through a systematic search for nuclear suppressors of a degenerative process displayed by the AS1-4 mutant. The PaTom70 protein shows 80% identity with its N. crassa homolog. The PaMdm10 protein displays 35.9% identity with its S. cerevisiae homolog, and cytological analyses show that the PaMDM10-1 mutant exhibits giant mitochondria, as does the S. cerevisiae mdm10-1 mutant. Mutations in PaTOM70 and PaMDM10 result in the accumulation of specific deleted mitochondrial genomes during the senescence process of the fungus. The phenotypic properties of the single- and double-mutant strains suggest a functional relationship between the Tom70 and Mdm10 proteins. These data emphasize the role of the mitochondrial outer membrane in the stability of the mitochondrial genome in an obligate aerobe, probably through the import process.

Self-selection of dietary protein and energy by broilers grown under a tropical climate: effect of feed particle size on the feed choice

Broilers, 2 wk of age, that had been previously adapted to energy: protein choice feeding, were offered corn (either ground, cracked, or presented as whole grains) and a protein concentrate (43.7% CP) in mash or pellet form. When corn was fed as whole grains, protein concentrate in the selected diet was significantly higher (35.1%) than with cracked corn (29.3%) or ground corn (29.1%). Presenting the concentrate as pellets resulted in a significantly higher concentration in the diet (32.7%) than when mash concentrate was fed (29.6%). Live BW at 4 and 6 wk of age were not significantly affected by feed texture. However, offering corn as whole grains or concentrate as pellets induced a significant improvement in feed efficiency. Total time to eat larger size particles (whole grains, pelleted concentrate) was significantly less than total time to eat ground corn or mash concentrate. Furthermore, the mean duration of the feeding bouts was two times shorter for whole grains (48 s) than for ground corn (98 s) and for pelleted concentrate (56 s) than for mash concentrate (114 s). Chickens ate whole grains or pellets at a significantly slower rate (number of pecks per second feeding time) than when eating ground corn or mash concentrate. There was a rejection during the first 24 h when the form of the concentrate (mash to pellets) was changed. Full adaptation to the new size of the concentrate required about 3 d.

Evaluation of gastric emptying function in clinical practice

In this retrospective analysis, we compared different methods to evaluate gastric emptying function, aiming to improve the sensitivity and the clinical availability of our diagnostic testing. In the first study, we compared, in 72 patients clinically suspected of gastroparesis, the emptying of a meal containing two solid nutrients with different disintegration rates: 111In-labeled scrambled eggs and 99Tc-labeled liver cubes. Gastric emptying of 111In-labeled egg was delayed in 12 of our patients and the evacuation of the 99Tc-labeled liver was prolonged in 19 patients. The choice of the nutrient was not important for the identification of diabetic gastroparesis (43% vs 57%; NS), but it was determinant in the case of patients suspected of idiopathic gastroparesis (12% were positive with the egg and 25% with the liver; P < 0.05). In the second study, we compared two different diagnostic methods in 46 patients: a simple radiological detection of the gastric emptying of radiopaque pellets, and the scintigraphic emptying of a solid meal containing 99Tc-labeled liver cubes. Both tests correlated perfectly in 78% of our patients. In 15% of the population (six of these seven patients were diabetics suspected of gastroparesis) the scintigraphic method was normal, while the evacuation of radiopaque pellets was delayed. For clinical purposes, we therefore propose: (1) the scintigraphic method should use liver rather than egg as a radiolabeled tracer in order to improve the sensitivity of the test for detection of gastroparesis; and (2) the radiological detection of radiopaque markers is a reliable and convenient method for the detection of gastroparesis in clinical practice. It is possibly more sensitive than scintigraphy.

Determination of Fish Flesh Content in Frozen Coated Fish Products (Modification of AOAC Official Method 971.13): Collaborative Study

An intralaboratory1collaborative study evaluated a modified version of AOAC Official Method 971.13 for determining the fish flesh content (FFC) in frozen coated fish products by comparing it with the on-line method. Eleven collaborators analyzed 36 products (a total of 6336 test samples). Each product targeted one of 4 percent fish flesh (PFF) levels (35,50,65, and 80). Products were manufactured from one of 3 raw materials (fillet blocks, minced blocks, and natural fillets) and processed in one of 4 forms (sticks, portions, formed portions, and fillets) and one of 4 styles (raw breaded, batter-dipped, precooked, and fully cooked). Each “official” test sample was tracked through the processing system and weighed (1) before battering and/or breading and, depending on product style, before frying; and (2) after battering and/or breading and, depending on product style, after frying; so that it served as its own control.

What is a bona fide mating-type gene? Internuclear complementation of mat mutants in Podospora anserina

In the heterothallic ascomycete Podospora anserina, the mating-type locus is occupied by two mutually exclusive sequences termed mat+ and mat-. The mat+ sequence contains only one gene, FPR1, while the mat- sequence contains three genes: FMR1, SMR1 and SMR2. Previous studies have demonstrated that FPR1 and FMR1 are required for fertilization. Further analyses have led to the hypothesis that mat+ and mat- genes establish a mat+ and mat- nuclear identity, allowing recognition between nuclei of opposite mating type within the syncytial cells formed after fertilization. This hypothesis was based on the phenotypes of strains bearing mutations in ectopic mat genes. Here we present an analysis of mutations in resident mat- genes which suggests that, unlike FMR1 and SMR2, SMR1 is not involved in establishing nuclear identity. In fact, mutations in these two genes impair nuclear recognition, leading to uniparental progeny, while mutations in SMR1 block the sexual process, probably at a step after nuclear recognition. The nuclear identity hypothesis has also been tested through internuclear complementation tests. In these experiments, the mat- mutants were crossed with a mat+ strain carrying the wild-type mat- genes. Our rationale was that internuclear complementation should not be possible for nuclear identity genes: the relevant genes should show nucleus-restricted expression, and diffusion of their products to other nuclei should not occur. This test confirmed that SMR1 is not a bona fide mat gene since it can fulfill its function whatever its location, in either a mat- or a mat+ nucleus, and even when present in both nuclei. SMR2, but not FMR1, behaves like a nuclear identity gene with respect to internuclear complementation tests. A model is proposed that tentatively explains the ambiguous behaviour of the FMR1 gene and clarifies the respective functions of the three mat- proteins.

Responses of meat-type chickens to choice feeding of diets differing in protein and energy from hatch to market weight

Chickens from three genetic stocks known to differ in growth potential consumed ad libitum either a single (control) diet or a choice of two diets that differed in protein and energy. Formulation of the choice diets was such that when mixed in specific proportions they provided single diets that decreased in protein and increased in energy over the experimental period. When comparisons of feeding regimens were made at a common age, body weights and feed efficiencies for all stocks were enhanced in chicks fed a single diet. When comparisons were made at a common body weight for controls, chickens fed the single diet were about 15% heavier than those given a dietary choice. For feed efficiency, however, the pattern remained for the faster growing stock whereas there was no difference between feeding regimens for the slower growing stock. Chicks provided a choice of diets had heavier abdominal fat pads and lighter breasts relative to body weight than those fed a single diet. With choice feeding, there were stock by diet interactions for dietary preferences through the first 9 d after hatch. Early on, the interactions resulted from the faster growing stocks exhibiting a greater preference for the diet higher in protein and lower in energy than the slower growing stock. By Day 5, however, the interaction occurred because stocks exhibited either no dietary preference or preferred the diet that was lower in protein and higher in energy. Regardless of genetic stock, at 9 d of age and thereafter there was a clear preference for the diet lower in protein and higher in energy than the diet higher in protein and lower in energy. These data for feed intake were consistent with behavioral observations that showed a preponderance of chicks eating from the feeder containing the diet lower in protein and higher in energy. Compared to a single diet, under choice feeding, energy utilization was negatively influenced more in the faster than slower growing stocks. Protein and sulfur amino acid utilization was not affected by feeding regimen in faster growing stocks, but was enhanced under choice feeding in the slower growing stock. Although lysine utilization was enhanced by choice feeding in all stocks, the effect was greater in the slower than in the faster growing ones. These data demonstrate that although broiler diets are formulated to enhance growth and overall feed efficiency, chicks that are provided a dietary choice of protein and energy do not eat to maximize growth or feed efficiency.

Methodological validation and clinical usefulness of carbon-14-urea breath test for documentation of presence and eradication of Helicobacter pylori infection

A simple [14C]urea breath test (C-14-UBT) was validated with aims of determining accuracy in documenting both the presence and proof of eradication of Helicobacter pylori infection.

METHODS

Fifty-six dyspeptic patients had endoscopy with biopsies and C-14-UBT. Eleven biopsy-proven H. pylori-negative patients allowed C-14-UBT normal value determination. Forty-three patients with recurrent peptic ulcer disease and biopsy-proven H. pylori infection were included in an antimicrobial eradication protocol. Endoscopy with biopsies and C-14-UBT were done again 8 wk after initiation of treatment in 35 patients. For C-14-UBT, 185 kBq (5 microCi) of [14C]urea was swallowed. Breath samples obtained up to 20 min were counted to calculate AS20, [(% 14CO2 dose excreted/mmol of CO2) x kg] at 20 min. Combined histologic and microbiologic analyses of antral biopsies were used as a gold standard.

RESULTS

The positivity value was set as AS20 > 0.33% (mean + 3 s.d. of AS20 in H. pylori-negative patients). Diagnosis of H. pylori infection was correct with C-14-UBT in 55/56 patients (44 true-positive, 11 true-negative and 1 false-negative; sensitivity = 98%; specificity = 100%). As a proof of eradication, C-14-UBT correctly classified 33/35 patients (5 true-positive, 28 true-negative and 2 false-positive; sensitivity = 100%; specificity = 93%). The C-14-UBT global performance yielded sensitivity, specificity and accuracy of 98%, 95% and 97%, respectively. A significant correlation (r = 0.84) was found between AS20 and the number of H. pylori colonies on culture.

CONCLUSION

This C-14-UBT is highly accurate both for diagnosis and proof of eradication of H. pylori infection and reflects the antral bacterial load. It is simple, fast and inexpensive, and it is therefore suitable for clinical practice.

Feed pecking in young chickens: new techniques of evaluation

Three techniques were compared: automated recording (A) of 2 h of feeding activities conveyed to a computer by constantly connected electronic balances, videotaping (V) of a closeup of the head of a chick during a feed-pecking session analyzed by focal sampling at reduced speed (16 times slower), strength of pecking (S) at feed particles recorded from a feeder-weight signal conveyed to a computer by a customized electronic balance at rapid speed (24 times/s). These techniques were applied to 16-18-day-old chicks fed either a complete feed or a split diet (whole grain wheat + a complementary feed). The two feeds had similar pellet forms. The complementary feed particles were eaten at a slower rate than the complete feed particles (A and V techniques). Wheat grains were pecked with a weaker measured strength than the pellets (technique S). Two pecks of three did not result in prehension of a feed particle and were categorized as "exploratory" pecks. For 75% of the time during a continuous pecking session the head of the chick was in a static position, suggesting a long period of observation of the feed between 2 consecutive pecks. Videotaping with slow-motion focal sampling (V) offers potential development for the study of food intake behavior of chickens.

Pharmacokinetics and metabolism of the novel anticonvulsant agent N-(2,6-dimethylphenyl)-5-methyl-3-isoxazolecarboxamide (D2624) in rats and humans

N-(2,6-dimethylphenyl)-5-methyl-3-isoxazolecarboxamide (D2624) belongs to a new series of experimental anticonvulsants related to lidocaine. This study was undertaken to understand the pharmacokinetics and metabolism of D2624 in rats and humans, with emphasis on the possible formation of 2,6-dimethylaniline (2,6-DMA). After oral administration of stable isotope-labeled parent drug to rats and GC/MS analysis of plasma samples, two metabolites were identified: D3017, which is the primary alcohol, and 2,6-DMA, formed by amide bond hydrolysis of either D2624 or D3017. In urine, three metabolites of D2624 were identified: namely D3017,2,6-DMA, and D3270 (which is the carboxylic acid derivative of D3017). Based on plasma AUC analysis, D3017 and 2,6-DMA accounted for > 90% of the dose of D2624. After oral administration, D2624 was found to be well absorbed (93%), but underwent extensive first-pass metabolism in the rat, thus resulting in 5.3% bioavailability. Rat and human liver microsomal preparations were capable of metabolizing D2624 to D3017 and 2,6-DMA. The formation of D3017 was NADPH-dependent, whereas 2,6-DMA formation was NADPH-independent and probably was catalyzed by amidase(s) enzymes. In a single-dose (25-225 mg) human volunteer study, the parent drug (D2624) was not detected in plasma at any dose, whereas 2,6-DMA was detected only at the two highest doses (150 and 225 mg). D3017 was detected after all doses of parent drug, with approximate dose proportionality in AUC and a half-life of 1.3-2.2 hr. The metabolic behavior observed in humans suggests there is a marked species difference in the oxidative and hydrolytic pathways of D2624.

Premature death in Podospora anserina: sporadic accumulation of the deleted mitochondrial genome, translational parameters and innocuity of the mating types

The Podospora anserina premature death syndrome was described as early growth arrest caused by a site-specific deletion of the mitochondrial genome (mtDNA) and occurring in strains displaying the genotype AS1-4 mat-. The AS1-4 mutation lies in a gene encoding a cytosolic ribosomal protein, while mat- is one of the two forms (mat- and mat+) of the mating-type locus. Here we show that, depending on culture conditions, death due to the accumulation of the deleted mtDNA molecule can occur in the AS1-4 mat+ context and can be delayed in the AS1-4 mat- background. Furthermore, we show that premature death and the classical senescence process are mutually exclusive. Several approaches permit the identification of the mat-linked gene involved in the appearance of premature death. This gene, rmp, exhibits two natural alleles, rmp- linked to mat- and rmp+ linked to mat+. The first is probably functional while the second probably carries a nonsense mutation and is sporadically expressed through natural suppression. A model is proposed that emphasizes the roles played by the AS1-4 mutation, the rmp gene, and environmental conditions in the accumulation of the deleted mitochondrial genome characteristic of this syndrome.