Parental body condition does not correlate with offspring sex-ratio in Cory's shearwater

We analyzed offspring sex ratio variation in Mediterranean Cory's Shearwater (Calonectris d. diomedea) during two consecutive breeding seasons in two colonies. We test for differential breeding conditions between years and colonies looking at several breeding parameters and parental condition. We then explored the relationship between offspring sex ratio and parental condition and breeding parameters. This species is sexually dimorphic with males larger and heavier than females; consequently we expected differential parental cost in rearing sexes, or a greater sensitivity of male chicks to adverse conditions, which may lead to biased sex ratios. Chicks were sexed molecularly by the amplification of the CHD genes. Offspring sex ratio did not differ from parity, either at hatching or fledging, regardless of the colony or year. However, parental body condition and breeding parameters such as egg size and breeding success were different between years and colonies. Nevertheless, neither nestling mortality nor body condition at fledging varied between years or colonies, suggesting that male and female chicks were probably not differentially affected by variability in breeding conditions.

Ecological and physiological variance in T-cell mediated immune response in Cory's shearwaters

T-cell mediated immune response (CMI) hasbeen widely studied in relation to individual andfitness components in birds. However, few studieshave simultaneously examined individual and socialfactors and habitat-mediated variance in theimmunity of chicks and adults from the samepopulation and in the same breeding season. Weinvestigated ecological and physiological variancein CMI of male and female nestlings and adults in abreeding population of Cory's Shearwaters(Calonectrisdiomedea) in theMediterranean Sea. Explanatory variables includedindividual traits (body condition, carbon andnitrogen stable isotope ratios, plasma totalproteins, triglycerides, uric acid, osmolarity,β-hydroxy-butyrate, erythrocyte meancorpuscular diameter, hematocrit, andhemoglobin) and burrow traits(temperature, isolation, and physicalstructure). During incubation, immune responseof adult males was significantly greater than thatof females. Nestlings exhibited a lower immuneresponse than adults. Ecological and physiologicalfactors affecting immune response differed betweenadults and nestlings. General linear models showedthat immune response in adult males was positivelyassociated with burrow isolation, suggesting thatmales breeding at higher densities suffer immunesystem suppression. In contrast, immune response inchicks was positively associated with bodycondition and plasma triglyceride levels.Therefore, adult immune response appears to beassociated with social stress, whereas a trade-offbetween immune function and fasting capability mayexist for nestlings. Our results, and those fromprevious studies, provide support for anasymmetrical influence of ecological andphysiological factors on the health of differentage and sex groups within a population, and for theimportance of simultaneously considering individualand population characteristics in intraspecificstudies of immune response.

Reencontro de Balanoglossus gigas Fr. Muller no litoral brasileiro

Re-finding of Balanoglossus gigas FR. MUULLER on the brasilian sea shore. Balanoglossus gigas, the giant Enteropneusta, has been described for the first time by Fritz Muller in his notes collected and published by Dr. HERMANN VON IHERING (1898, pg. 35). FR. MULLER found the Balanoglossus on the coats of the State of Santa Catarina in 1884. Once again in 1885 several specimens of that animal were captured by FR. MULLER in the same place. Since that time up to now no references on the occurrence of this animal have been found in the zoological bibliography. During the spring of 1948 Prof. W. BESNARD, Director of he Instituto Paulista de Oceanografia saw some signals indicating the existence of Balanoglossus at the beach of São Sebastião, State of São Paulo. From 1948 to now several attempts have been made to catch the animal alive and complete. On the last September during a shorts visit to the beach of São Sebastião one Balanoglossus was captured and brought to the Department of General and Animal Physiology in good conditions. The animal measured 1.80 m in length. It seems to be the largest Balanoglossus known. According to the descriptions of SPENGEL (1893, pg. 158), and VAN DER HORST (1939) pg. 717) it was possible to identify this Enteropneusta as Balanoglossus gigas FR. MULLER, refound at the Brazilian coast sixty six years after its discovery by FR. MÜLLER.

Effects of glucose, propionate and splanchnic hormones on neuropeptide mRNA concentrations in the ovine hypothalamus

The capacity for glucose, propionate or hormones of splanchnic origin to influence appetite by directly regulating the expression of neuropeptides in the feeding centres of the hypothalamus of the ruminant is not described. Therefore, our objective was to measure the direct effect of metabolites (glucose and propionate) or hormones [insulin, cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1) and polypeptide YY (PYY)] on hypothalamic mRNA concentrations for neuropeptide Y (NPY), agouti-related peptide (AgRP) and proopiomelanocortin (POMC) following in vitro incubation. Hypothalamic tissue from 4- to 5-month-old lambs was obtained at slaughter and immediately incubated in culture media for 2 h at 36 °C. Treatments included a control Dulbecco’s modified Eagle medium (DMEM) containing 1 mm glucose or DMEM with the following additions: 10 mm glucose, 1 mm propionate, 1 nm insulin, 120 pm GLP-1, 100 pm PYY, 80 pm CCK or 10 mm glucose plus 1 nm insulin. The abundance of mRNA for NPY, AgRP and POMC was measured using quantitative reverse transcriptase PCR. Fisher’s protected LSD test was used to compare changes in relative mRNA concentrations for the hypothalamus incubated in the control media vs. the rest of the treatments. The media containing glucose plus insulin increased POMC mRNA concentration (p < 0.05), but did not affect NPY or AgRP mRNA concentration. There were no effects observed for the other treatments (p > 0.20). Results of the present study are consistent with the concept that effects of propionate on feed intake in ruminants is not mediated through direct effects on the hypothalamus, and that insulin is required for an effect of glucose on hypothalamic POMC expression.

Impact of variation in structure of condensed tannins from sainfoin (Onobrychis viciifolia) on in vitro ruminal methan production and fermentation characteristics

Our study investigated the effects of condensed tannins (CT) on rumen in vitro methane (CH4) production and fermentation characteristics by incubating lucerne in buffered rumen fluid in combination with different CT extracts at 0 (control), 40, 80 and 120 g CT/kg of substrate DM. Condensed tannins were extracted from four sainfoin accessions: Rees ‘A’, CPI63763, Cotswold Common and CPI63767. Gas production (GP) was measured using a fully automated GP apparatus with CH4 measured at distinct time points. Condensed tannins differed substantially in terms of polymer size and varied from 13 (Rees ‘A’) to 73 (CPI63767) mean degree of polymerization, but had relatively similar characteristics in terms of CT content, procyanidin: prodelphinidin (PC: PD) and cis:trans ratios. Compared to control, addition of CT from CPI63767 and CPI63763 at 80 and 120 g CT/kg of substrate DM reduced CH4 by 43% and 65%, and by 23% and 57%, respectively, after 24-h incubation. Similarly, CT from Rees ‘A’ and Cotswold Common reduced CH4 by 26% and 46%, and by 28% and 46% respectively. Addition of increasing level of CT linearly reduced the maximum rates of GP and CH4 production, and the estimated in vitro organic matter digestibility. There was a negative linear and quadratic (p < 0.01) relation between CT concentration and total volatile fatty acid (VFA) production. Inclusion of 80 and 120 g CT/kg of substrate DM reduced (p < 0.001) branched-chain VFA production and acetate: propionate ratio and was lowest for CPI63767. A decrease in proteolytic activity as indirectly shown by a change in VFA composition favouring a shift towards propionate and reduction in branched-chain VFA production varied with type of CT and was highest for CPI63767. In conclusion, these results suggest that tannin polymer size is an important factor affecting in vitro CH4 production which may be linked to the CT interaction with dietary substrate or microbial cells.

Feeding strategy with alternate fasting and refeeding: effects on farmed pacu production

P>A 36-day trial was conducted to determine the effects of repetitive periods of food restriction and refeeding on growth and energy metabolism in pacu (Piaractus mesopotamicus). A total 264 juvenile fish (36.9 +/- 2.8 g) were fed with the experimental diet for 36 days using three regimes: (i) feeding daily to satiation (FD); (ii) no feed for 3 days, then feeding the same amount offered to the control groups for the next 3 days (NF/R controlled); and (iii) no feed for 3 days, then feeding to apparent satiation for the next 3 days (NF/R at satiation). The treatments were distributed into four tanks each. WG and SGR were higher in FD group. Fish refed showed hyperphagia just up to the second day of refeeding. The worst feed conversion rate and the lowest protein efficiency ratio were found in fish NF/R controlled. The lowest values of visceral fat somatic index were found in both fasted fish groups, particularly in NF/R at satiation. The LL and glycogen concentrations, and the hepatosomatic index were all elevated in both feed restricted fish. Muscle lipid showed a tendency to decrease after the cycle of fasting and refeeding. Plasma free fatty acids and glucose levels were elevated in fish subjected to feeding restrictions while serum triglycerides levels were reduced. Triiodothyronine levels were significantly depressed in fish from the NF/R-controlled group and remained at the same levels as the control fish in fish NF/R at satiation. Results indicated that fish subjected to cyclic periods of 3-day satiation or controlled feeding after 3-days of fasting were unable to achieve the final body weight of fish fed to satiation after 36 days.

Respiratory metabolism of Camponotus rufipes ants: Brood and adults

The respiratory metabolism of immature forms (eggs, larvae, prepupae and pupae) of Camponotus rufipes (Hymenoptera: Formicidae) was studied at 25 degrees C, using a Warburg respirometer. Mean respiratory rates (mu l O gamma mg(-1) live weight.hr(-1)) for eggs, first instars, second instars, third instars, fourth instars, prepupae, and pupae were respectively: 2.53, 5.07, 1.23, 0.32, 0.22, 0.19 and 0.13. Adult workers with body mass between 20 and 30 mg had a mean respiratory rate of 0.43. The high respiratory rate in first instars probably reflects, besides the size influence, the metabolic costs of differentiation that occurs in this phase. (C) 1998 Published by Elsevier B.V.

Digestibility for dogs and cats of meat and bone meal processed at two different temperature and pressure levels

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Effects of six carbohydrate sources on dog diet digestibility and post-prandial glucose and insulin response

The effects of six extruded diets with different starch sources (cassava flour, brewer's rice, corn, sorghum, peas or lentils) on dog total tract apparent digestibility and glycemic and insulinemic response were investigated. The experiment was carried out on thirty-six dogs with six dogs per diet in a completely randomized design. The diets containing brewer's rice and cassava flour presented the greatest digestibility of dry matter, organic matter and gross energy (p < 0.05), followed by corn and sorghum; pea and lentil diets had the lowest. Starch digestibility was greater than 98% in all diets and was greater for brewer's rice and cassava flour than for lentils and peas diets (p < 0.05). Dogs' immediate post-prandial glucose and insulin responses (AUC <= 30 min) were greater for brewer's rice, corn, and cassava flour diets (p < 0.05), and later meal responses (AUC >= 30 min) were greater for sorghum, lentil and pea diets (p < 0.05). Variations in diet digestibility and post-prandial response can be explained by differences in chemical composition of each starch source including fibre content and starch granule structure. The nutritional particularities of each starch ingredient can be explored through diet formulations designed to modulate glycemic response. However, more studies are required to support these.

Protein requirements for Blue-fronted Amazon (Amazona aestiva) growth

The objective of this study was to evaluate the protein requirements for hand-rearing Blue-fronted Amazon parrots (Amazona aestiva). Forty hatchlings were fed semi-purified diets containing one of four (as-fed basis) protein levels: 13%, 18%, 23% and 28%. The experiment was carried out in a randomized block design with the initial weight of the nestling as the blocking factor and 10 parrots per protein level. Regression analysis was used to determine relationships between protein level and biometric measurements. The data indicated that 13% crude protein supported nestling growth with 18% being the minimum tested level required for maximum development. The optimal protein concentration for maximum weight gain was 24.4% (p = 0.08; r(2) = 0.25), tail length 23.7% (p = 0.09; r(2) = 0.19), wing length 23.0% (p = 0.07; r(2) = 0.17), tarsus length 21.3% (p = 0.06; r(2) = 0.10) and tarsus width 21.4% (p = 0.07; r(2) = 0.09). Tarsus measurements were larger in males (p < 0.05), indicating that sex must be considered when studying developing psittacines. These results were obtained using a highly digestible protein and a diet with moderate metabolizable energy levels.

Nutrient digestibility, but not mineral absorption, is age-dependent in cats

Availability of nutrients is influenced by extremes of age, and a better characterization of this influence is necessary for appropriate development of foods and nutritional management throughout life stages of cats. This study investigated nutrient digestibility, mineral absorption, faeces and urine production in three groups of six young, mature and old cats fed two diets containing different energy densities. Apparent digestibility and mineral absorption were calculated by total collection method and values were tested with ANOVA and regression analysis. A quadratic relationship was detected between age and digestibility of dry matter, organic matter, crude protein, acid-hydrolysed fat and starch in the low-energy diet. Starch digestibility showed the same response in the high-energy diet. Young adult cats had intermediate digestibility, mature cats the highest and old cats the lowest. Mineral absorption (calcium, phosphorus, magnesium, sodium, potassium and chloride) and urinary pH were not different among groups. These findings confirm previous studies that found low digestibility of nutrients in some old cats, and support evidence that this trend is even more important in less digestible dry foods. on the contrary, data suggest that mineral formulations do not need to be varied in diets for adult cats of different ages.

Geographic variations in the composition of myotoxins from Bothrops neuwiedi snake venoms: biochemical characterization and biological activity

(1) Venom pools from Bothrops neuwiedi (Bn) and from two subspecies, namely Bothrops neuwiedi pauloensis (Bnp) and Bothrops neuwiedi urutu (Bnu), collected in the States of São Paulo (SP) and Minas Gerais (MG), Brazil, were electrophoretically examined. Basic toxins with different isoelectric points were identified in the venom collected in São Paulo (BnSP). These toxins were absent in the corresponding pools from Minas Gerais (BnMG, BnpMG and BnuMG). (2) BnSP, but not BnMG, BnpMG or BnuMG, showed two myotoxins (pI congruent to 8.6 and 8.8, respectively) which were isolated by ion-exchange chromatography on CM-Sepharose. (3) From BnMG, three myotoxic isoforms (pI congruent to 8.2 and M-r = 13600) were isolated by chromatography on CM-Sepharose followed by reversed-phase high-performance liquid chromatography. (4) the chemical and biological characterization of these toxins showed a high similarity with the Lys-49 myotoxins from other bothropic venoms. (5) Doses up to 5 LD50 (i.p.) of p-bromophenacyl bromide alkylated BnSP-7 caused a total loss of lethality in 18-22-g mice, thus indicating that the LD50 was increased by greater than 5-fold. At this dose myotoxicity was also not detectable, but the edematogenic activity on the rat paw apparently did not change. (C) 1998 Elsevier B.V. All rights reserved.

Metabolic changes in Brycon cephalus (Teleostei, Characidae) during post-feeding and fasting

Metabolic changes during the transition from post-feeding to fasting were studied in Brycon cephalus, an omnivorous teleost from the Amazon Basin in Brazil. Body weight and somatic indices (liver and digestive tract), glycogen and glucose content in liver and muscle, as well as plasma glucose, free fatty acids (FFA), insulin and glucagon levels of B. cephalus, were measured at 0, 12, 24, 48, 72, 120, 168 and 336 h after the last feeding. At time 0 h (the moment of food administration, 09.00 h) plasma levels of insulin and glucagon were already high, and relatively high values were maintained until 24 h post-feeding. Glycemia was 6.42 +/- 0.82 mM immediately after food ingestion and 7.53 +/- 1.12 MM at 12 h. Simultaneously, a postprandial replenishment of liver and muscle glycogen reserves was observed. Subsequently, a sharp decrease of plasma insulin occurred, from 7.19 +/- 0.83 ng/ml at 24 h of fasting to 5.27 +/- 0.58 ng/ml at 48 h. This decrease coincided with the drop in liver glucose and liver glycogen, which reached the lowest value at 72 h of fasting (328.56 +/- 192.13 and 70.33 +/- 14.13 mumol/g, respectively). Liver glucose increased after 120 h and reached a peak 168 h post-feeding, which suggests that hepatic gluconeogenesis is occurring. Plasma FFA levels were low after 120 and 168 h and increased again at 336 h of fasting. During the transition from post-feeding to fast condition in B. cephalus, the balance between circulating insulin and glucagon quickly adjust its metabolism to the ingestion or deprivation of food. (C) 2002 Elsevier B.V. All rights reserved.

Aerobic metabolism during predation by a boid snake

We quantified the oxygen uptake rates ((V) over dot O-2) and time spent, during the constriction, inspection, and ingestion of prey of different relative sizes, by the prey-constricting boid snake Boa constrictor amarali. Time spent in prey constriction varied from 7.6 to 16.3 min, and (V) over dot O-2 during prey constriction increased 6.8-fold above resting values. This was the most energy expensive predation phase but neither time spent nor metabolic rate during this phase were correlated with prey size. Similarly, prey size did not affect the (V) over dot O-2 or duration of prey inspection. Prey ingestion time, on the other hand, increased linearly with prey size although (V) over dot O-2 during this phase, which increased 4.9-fold above resting levels, was not affected by prey size. The increase in mechanical difficulty of ingesting larger prey, therefore, was associated with longer ingestion times rather than proportional increases in the level of metabolic effort. The data indicate that prey constriction and ingestion are largely sustained by glycolysis and the intervening phase of prey inspection may allow recovery between these two predatory phases with high metabolic demands. The total amount of energy spent by B. c. amarali to constrict, inspect, and ingest prey of sizes varying from 5 to 40% of snake body mass varied inversely from 0.21 to 0.11% of the energy assimilated from the prey, respectively. Thus, prey size was not limited by the energetic cost of predation. on the contrary, snakes feeding on larger prey were rewarded with larger energetic returns, in accordance with explanations of the evolution of snake feeding specializations. (C) 2002 Elsevier B.V. All rights reserved.

Effects of temperature and hypercapnia on ventilation and breathing pattern in the lizard Uromastyx aegyptius microlepis

In most reptiles, the ventilatory response to hypercapnia consists of large increases in tidal volume (V-T), whereas the effects on breathing frequency (f(R)) are more variable. The increased V-T seems to arise from direct inhibition of pulmonary stretch receptors. Most reptiles also exhibit a transitory increase in ventilation upon removal of CO2 and this post-hypercapnic hyperpnea may consist of changes in both V-T and f(R). While it is well established that increased body temperature augments the ventilatory response to hypercapnia, the effects of temperature on the post-hypercapnic hyperpnea is less described. In the present study, we characterise the ventilatory response of the agamid lizard Uromastyx aegyptius to hypercapnia and upon the return to air at 25 and 35 degreesC. At both temperatures, hypercapnia caused large increases in V-T and small reductions in f(R), that were most pronounced at the higher temperature. The post-hypercapnic hyperpnea, which mainly consisted of increased fR, was numerically larger at 35 compared to 25 degreesC. However, when expressed as a proportion of the levels of ventilation reached during steady-state hypercapnia, the post-hypercapnic hyperpnea was largest at 25 degreesC. Some individuals exhibited buccal pumping where each expiratory thoracic breath was followed by numerous small forced inhalations caused by contractions of the buccal cavity. This breathing pattern was most pronounced during severe hypercapnia and particularly evident during the post-hypercapnic hyperpnea. (C) 2002 Published by Elsevier B.V.