Rat Carcasses Research Articles

The effects of a high dosage of creatine and caffeine supplementation on the lean body mass composition of rats submitted to vertical jumping training.

BackgroundThe influences of creatine and caffeine supplementation associated with power exercise on lean body mass (LBM) composition are not clear. The purpose of this research was to determine whether supplementation with high doses of creatine and caffeine, either solely or combined, affects the LBM composition of rats submitted to vertical jumping training.MethodsMale Wistar rats were randomly divided into 8 groups: Sedentary (S) or Exercised (E) [placebo (Pl), creatine (Cr), caffeine (Caf) or creatine plus caffeine (CrCaf)]. The supplemented groups received creatine [load: 0.430 g/kg of body weight (BW) for 7 days; and maintenance: 0.143 g/kg of BW for 35 days], caffeine (15 mg/kg of BW for 42 days) or creatine plus caffeine. The exercised groups underwent a vertical jump training regime (load: 20 - 50% of BW, 4 sets of 10 jumps interspersed with 1 min resting intervals), 5 days/wk, for 6 weeks. LBM composition was evaluated by portions of water, protein and fat in the rat carcass. Data were submitted to ANOVA followed by the Tukey post hoc test and Student's t test.ResultsExercised animals presented a lower carcass weight (10.9%; P = 0.01), as compared to sedentary animals. However, no effect of supplementation was observed on carcass weight (P > 0.05). There were no significant differences among the groups (P > 0.05) for percentage of water in the carcass. The percentage of fat in the group SCr was higher than in the groups SCaf and ECr (P < 0.05). A higher percentage of protein was observed in the groups EPl and ECaf when compared to the groups SPl and SCaf (P < 0.001). The percentage of fat in the carcass decreased (P < 0.001), while those of water and protein increased (P < 0.05) in exercised animals, compared to sedentary animals. Caffeine groups presented reduced percentage of fat when compared to creatine supplemented groups (P < 0.05).ConclusionsHigh combined doses of creatine and caffeine does not affect the LBM composition of either sedentary or exercised rats, however, caffeine supplementation alone reduces the percentage of fat. Vertical jumping training increases the percentages of water and protein and reduces the fat percentage in rats.

Gene Expression During Blow Fly Development: Improving the Precision of Age Estimates in Forensic Entomology*,†

Forensic entomologists use size and developmental stage to estimate blow fly age, and from those, a postmortem interval. Since such estimates are generally accurate but often lack precision, particularly in the older developmental stages, alternative aging methods would be advantageous. Presented here is a means of incorporating developmentally regulated gene expression levels into traditional stage and size data, with a goal of more precisely estimating developmental age of immature Lucilia sericata. Generalized additive models of development showed improved statistical support compared to models that did not include gene expression data, resulting in an increase in estimate precision, especially for postfeeding third instars and pupae. The models were then used to make blind estimates of development for 86 immature L. sericata raised on rat carcasses. Overall, inclusion of gene expression data resulted in increased precision in aging blow flies.

Convergent evolution of carrion and faecal scent mimicry in fly-pollinated angiosperm flowers and a stinkhorn fungus

Flowers of many angiosperms attract fly pollinators through mimicry of animal carrion and faeces. This phenomenon of “sapromyiophily” is also evident in the sporophytes of some mosses and fruiting bodies of “stinkhorn” fungi, both of which use flies as agents of spore dispersal. We studied the scent chemistry of a stinkhorn fungus ( Clathrus archeri) and seven fly-pollinated plant species with foetid odours to determine the degree to which these organisms mimic the scent of carrion and faeces (reference scent samples were collected from rotting meat, a rat carcass and horse and dog faeces), as well as the degree of convergent evolution between the fungus and angiosperm flowers. We found that scents of both the fungus and angiosperms tended to contain compounds typical of carrion, such as oligosulphides, and of faeces, such as phenol, indole and p-cresol. This study provides compelling new evidence for mimicry of carrion and faeces, as well as a striking pattern of convergence in the putrid scents of the fungus and the angiosperms, relative to those of confamilial species. The syndrome of sapromyiophily thus encompasses at least two kingdoms (Plantae and Fungi) and provides an effective means of exploiting flies as agents of pollen and spore dispersal.

Effect of Investigator Disturbance in Experimental Forensic Entomology: Carcass Biomass Loss and Temperature

Often carrion decomposition studies are conducted using a single carcass or a few carcasses sampled repeatedly through time to reveal trends in succession community composition. Measurements of biomass and other abiotic parameters (e.g., temperature) are often collected on the same carcasses but are rarely a focal point of the studies. This study investigated the effects that repeated sampling during experiments have on the decomposition of carrion, measured as both gross biomass (carcass plus fauna) and net biomass (carcass only), on carcasses disturbed on every visit (with weighing only or also with the collection of fauna) and on carcasses disturbed only once. Each trial lasted at least 21 days, with samples taken in triplicate. Rat carcasses used in this study were placed in the field on the same day and either weighed on every visit or ignored until a given day. Internal and ambient air temperatures were recorded on each carcass at the time of sampling and on undisturbed carcasses using temperature loggers. The presence of succession fauna did not result in significant biomass loss on most days; however, there were individual days early in decomposition (days 3 through 6) when the succession fauna comprised a large portion of the gross biomass. With the exception of biomass loss by the emigration of maggots on days 4 and 5, neither repeated weighing of the carcasses nor repeated weighing and faunal sampling of the carcasses statistically affected the rate of biomass loss. Internal temperatures of carcasses sampled repeatedly were frequently 2-5°C lower than those that had not been disturbed, and ambient temperatures differed significantly depending on the location of measurement device. Results indicate that methods used historically for biomass loss determination in experimental forensic entomology studies are adequate, but further refinements to experimental methodology are desirable.

Carrion decomposition and nutrient cycling in a semiarid shrub–steppe ecosystem

Vertebrate carrion decomposition and nutrient cycling have both direct and indirect effects on the soil properties, fauna, and flora associated with an animal's carcass. While few comprehensive quantitative studies have been undertaken, those that have show considerable variability in decomposition processes and rates, their regulating variables, and the resultant ecosystem effects. In this two‐part study, decomposition rates of vertebrate species were measured in a semiarid, shrub–steppe environment (Wyoming, USA). First, decomposition loss rates of mass, energy, and nutrients were measured for rat carcasses (Rattus norvegicus) in four seasons and two microsites (surface and underground burrows). Decomposition rates varied significantly between microsites (burrow &gt; surface in spring and summer) and among seasons (spring &gt; summer &gt; autumn ≈ winter), with mass loss amounts linearly correlated with ambient air temperatures. Energy and nutrient losses were related to phased carcass organ/tissue losses, with energy, K, Na, N, and S being lost more quickly than skeletal components (P, Mg, Ca). Overall, the nutrient loss sequence was K = Na &gt; N = S &gt; P = Mg &gt; Ca. Carcass quality (N concentration) declined through time as a function of decay stage. Second, decomposition rates of 10 vertebrate species (mule deer [Odocoileus hemionus], dog [Canis familiaris], white‐tailed jackrabbit [Lepus townsendii], Uinta ground squirrel [Spermophilus armatus], least chipmunk [Tamias minimus], deer mouse [Peromyscus maniculatus], Magpie [Pica hudsonia], Sage Sparrow [Amphispiza belli], terrestrial garter snake [Thamnophis elegans], and northern leopard frog [Lithobates pipiens]) were measured with vertebrate scavengers present or absent. Mass loss rates varied among species and were generally faster in the presence of scavengers. Carcass body mass, N content, or labile/recalcitrant fractions did not correlate with decomposition rate, though surface area to volume ratios of mammal carcasses were positively correlated with wet‐mass decomposition rate. Nutrient measures of sub‐carcass soils showed soil N, P, and Na increased during decomposition. Increased soil nutrient amounts represented up to 15.6% of the available carcass N, 28.8% of carcass P, and 28.7% of carcass Na. At a landscape scale in the shrub–steppe ecosystem, carrion decomposition constituted &lt;1% of the nutrient‐cycling budget but contributed significantly to localized soil nutrient dynamics.

Swine CAFOs &amp; Novel H1N1 Flu: Separating Facts from Fears

With cases documented in more than 170 countries, the global swine flu pandemic that erupted in spring 2009 remains a serious public health problem. Caused by a strain of H1N1 influenza virus, which is normally found in pigs, the flu now known as novel H1N1 has so far been less severe than regular seasonal flu in terms of deaths and hospitalizations. Yet given its remarkable capacity for human-to-human transmission and a widespread lack of immunity among potentially exposed people, it’s likely the number of cases will rise during the flu season later this fall and winter, according to many public health experts. Given that possibility, enormous resources are being mobilized to address novel H1N1, with an emphasis on vaccine development, education, and efforts to its limit its movements among human communities. Yet one potential source of the original outbreak—factory swine farming in concentrated animal feeding operations (CAFOs)—has received comparatively little attention by public health officials. CAFOs house animals by the thousands in crowded indoor facilities. But the same economy-of-scale efficiencies that allow CAFOs to produce affordable meat for so many consumers also facilitate the mutation of viral pathogens into novel strains that can be passed on to farm workers and veterinarians, according to Gregory Gray, director of the Center for Emerging Infectious Diseases at the University of Iowa College of Public Health. “When respiratory viruses get into these confinement facilities, they have continual opportunity to replicate, mutate, reassort, and recombine into novel strains,” Gray explains. “The best surrogates we can find in the human population are prisons, military bases, ships, or schools. But respiratory viruses can run quickly through these [human] populations and then burn out, whereas in CAFOs—which often have continual introductions of [unexposed] animals—there’s a much greater potential for the viruses to spread and become endemic.” Gray says workers exposed routinely to livestock can pass these zoonotic infections—which transmit readily among humans and animals—on to the wider public. However, public health agencies that monitor risks from zoonotic infections routinely overlook CAFO workers, according to Ellen Silbergeld, a professor at the Johns Hopkins Bloomberg School of Public Health. And animal disease sampling data collected by the food animal industry typically are not shared publicly, according to Gray, although such data could reveal how novel pathogens evolve in CAFOs and how they might move among animals, workers, and the broader community. Experts believe that without these data, society has a diminished capacity to detect and respond to new zoonotic threats before they become more widespread.

A COMPARISON OF DEVELOPMENT TIMES FOR Protophormia terraenovae (R-D) REARED ON DIFFERENT FOOD SUBSTRATES

ABSTRACTExperiments were conducted to determine whether a specific larval substrate impacted immature development rates. Protophormia terraenovae was raised on beef organs and compared with whole carcasses (rat), to determine if discrepancies in development times were observed. The minimum development time on beef liver was the most consistent with the rat carcass but a significant difference between all substrates was found after the third instar. These differences can be explained by the differences found between heart and muscle and the other substrates. Often length of the larvae is used to estimate insect age and so Day 2 measuring of weight, length, and width of the pupae was undertaken. Significant differences were found for all parameters measured on each of the substrates. As a result, the use of these measurements should not be done for P. terraenovae due to conflicting rearing substrates. Significant differences within substrates were only found for weight of insects developing on heart and length of insects developing on muscle. There was no significant difference in survival from first instar to the adult stage on any of the substrates but personal observation suggested that mortality was higher in insects developing on the brain tissue.

Factors affecting overwinter survival of the American burying beetle, Nicrophorus americanus (Coleoptera: Silphidae)

The endangered American burying beetle (Nicrophorus americanus) is relatively abundant at Fort Chaffee Maneuver Training Center in northwestern Arkansas. There is a paucity of basic life-history information available, particularly with respect to factors affecting overwintering success. In a field experiment we: (1) captured beetles at Fort Chaffee; (2) bred them in captivity; (3) in the fall on Fort Chaffee placed offspring individually in well-ventilated, lidded 21.1-l buckets containing original soil plugs in grassland or woodland, either provisioned or not with a rat carcass as potential food; (4) overwintered the beetles; (5) checked in the spring to determine survival; and (6) released surviving beetles. Overall, 59.6% of 104 beetles survived the winter, with 77.1% and 44.6% survival in provisioned and nonprovisioned buckets, respectively. No differences were evident between habitats. Beetle age was an important survival predictor, with older beetles having a higher survival probability, but only if nonprovisioned. Gender and body size were not predictive of survival. Many surviving beetles were at or near the surface; depth averaged 6.0 cm, with some as deep as 20 cm. Our findings suggest that American burying beetles will have a higher probability of overwinter survival if carcasses are readily available as winter approaches.

Fat storage is partially dependent on vagal activity and insulin secretion of hypothalamic obese rat

Hypothalamic MSG-obese rats show hyperinsulinemia and tissue insulin resistance, and they display intense parasympathetic activity. Current analysis investigates whether early subdiaphragmatic vagotomy prevents tissue insulin sensitivity impairment in adult obese MSG-rats. Hypothalamic obesity was induced by MSG (4 mg/g BW), daily, from birth up to 5 days. Control animals receiving saline solution. On the 30th day rats underwent bilateral subdiaphragmatic vagotomy or sham surgery. An intravenous glucose tolerance test (i.v.GTT) was performed when rats turned 90 days old. Total white fat tissue (WAT) from rat carcass was extracted and isolated; the interscapular brown fat tissue (IBAT) was weighed. Rather than blocking obesity, vagotomy reduced WAT and IBAT in MSG-obese rats when the latter were compared to sham MSG-rats. High blood fasting insulin and normal glucose levels were also observed in MSG-obese rats. Although glucose intolerance, high insulin secretion, and significant insulin resistance were recorded, vagotomy improved fasting insulinemia, glucose tolerance and insulin tissue sensitivity in MSG-obese rats. Results suggest that increased fat accumulation is caused, at least in part, by high blood insulin concentration, and enhanced parasympathetic activity on MSG-obese rats.

A checklist of arthropods associated with rat carrion in a montane locality of northern Venezuela

This is the first report of arthropods associated with carrion in Venezuela, using laboratory bred rats ( Rattus norvegicus). Rat carcasses were exposed to colonization by arthropods in neighboring montane savanna and cloud forest habitats in the state of Miranda. The taxonomic composition of the arthropods varied between both ecosystems. Scarabaeidae, Silphidae, Micropezidae, Phoridae, Vespidae and one species of ant, were collected only in the cloud forest. Dermestes maculatus, Chrysomya albiceps, Termitidae and most species of ants, were found only in the savanna. Fourteen species were considered to be of primary forensic importance: D. maculatus, Oxelytrum discicolle, Calliphora sp., Cochliomyia macellaria, Compsomyiops sp., C. albiceps, Phaenicia cuprina, P. sericata, P. eximia, Fannia sp., Puliciphora sp., Megaselia scalaris, Ravina sp. and Sarcophaga sp.

The Nocturnal Oviposition Behavior of Carrion Flies in Rural and Urban Environments: Methodological Problems and Forensic Implications

ABSTRACTUnequivocal identification of the time at which larvae are deposited upon a carcass is essential for applying maggots as estimators of the post-mortem interval of that carcass. However, there is controversy as to whether flies oviposit at night or not. Nocturnal exposure of rat carcasses at three sites in the Cincinnati metropolitan region was used to examine this behavior for two field seasons, 2005 and 2006. In the 2005 field season, nocturnally exposed bait rats were observed to harbor live larvae following a maturation period, but all of the positive results were discovered to have resulted from post-exposure contamination. In the 2006 field season several methods were changed to correct for contamination and in that field season, nocturnal ovipositing was not found to occur.

Components of Developmental Plasticity in a Michigan Population of &lt;I&gt;Lucilia sericata&lt;/I&gt; (Diptera: Calliphoridae)

Forensic entomologists rely on laboratory growth data to estimate the time of blow fly colonization on human remains. Several data sets exist for the development of the common blow fly Lucilia sericata (Meigen) (Diptera: Calliphoridae), and although they generally describe similar rates of preadult development, all vary. Such differences could be explained by genetic variation, environmental (rearing) variation, or both. In the study presented here, flies from a single population were reared under variable conditions of food moisture, substrate type, substrate freshness, and sampling, to determine the effect each had on developmental time. Cohorts were tested in a single incubator at a single temperature and humidity, to eliminate effects of undesired environmental variation. Fly developmental times were significantly influenced by multiple laboratory rearing treatments; food moisture, transferring postfeeding larvae to fresh substrate, and destructive sampling affected different stages of development. Developmental times ranged from 329 to 505.5 h, covering the spectrum of variation observed in published data sets. Growth was then compared with larval development on rat carcasses under the same environmental conditions, establishing a link between laboratory-controlled growth and development on carrion. Cohorts raised on rats matured to adulthood between 333 and 337 h, which was best mimicked by the fastest growth treatment observed under laboratory conditions. The large environmental influence on development observed in this study could affect forensic entomology casework and accentuates the need for a standardized means of rearing flies in a laboratory setting that is relevant to decomposition on a corpse.

Effect of investigator disturbance in experimental forensic entomology: succession and community composition

Carrion insect succession studies have historically used repeated sampling of single or a few carcasses to produce data, either weighing the carcasses, removing a qualitative subsample of the fauna present, or both, on every visit over the course of decomposition and succession. This study, conducted in a set of related experimental hypotheses with two trials in a single season, investigated the effect that repeated sampling has on insect succession, determined by the number of taxa collected on each visit and by community composition. Each trial lasted at least 21 days, with daily visits on the first 14 days. Rat carcasses used in this study were all placed in the field on the same day, but then either sampled qualitatively on every visit (similar to most succession studies) or ignored until a given day of succession, when they were sampled qualitatively (a subsample) and then destructively sampled in their entirety. Carcasses sampled on every visit were in two groups: those from which only a sample of the fauna was taken and those from which a sample of fauna was taken and the carcass was weighed for biomass determination. Of the carcasses visited only once, the number of taxa in subsamples was compared to the actual number of taxa present when the carcass was destructively sampled to determine if the subsamples adequately represented the total carcass fauna. Data from the qualitative subsamples of those carcasses visited only once were also compared to data collected from carcasses that were sampled on every visit to investigate the effect of the repeated sampling. A total of 39 taxa were collected from carcasses during the study and the component taxa are discussed individually in relation to their role in succession. Number of taxa differed on only one visit between the qualitative subsamples and the actual number of taxa present, primarily because the organisms missed by the qualitative sampling were cryptic (hidden deep within body cavities) or rare (only represented by very few specimens). There were no differences discovered between number of taxa in qualitative subsamples from carcasses sampled repeatedly (with or without biomass determinations) and those sampled only a single time. Community composition differed considerably in later stages of decomposition, with disparate communities due primarily to small numbers of rare taxa. These results indicate that the methods used historically for community composition determination in experimental forensic entomology are generally adequate.

Encontro do parasitóide Tachinaephagus zealandicus (Ashmead) (Hymenoptera: Encyrtidae) em pupas de Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) em carcaça de rato

This study reports the occurrence of Tachinaephagus zealandicus (Ashmead) (Hymenoptera: Encyrtidae) parasitizing pupae of Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) associated with a decomposing rat carcass in a secondary wood area in Campinas, SP. The parasitism rate was 91.8%.

Artrópodes associados às carcaças de pequenos roedores expostas em área de formação vegetal secundária no município de Campinas, SP

Although studies of the post-mortem fate of human corpses are of forensic interest, and in natural environments large animals become available to insect colonization soon after death, the fate of the vast number of small carcasses in some habitats, as well as the parameters that lead this process, are not objective of important investigations. Due to this situation, decomposition studies of small rodent carcasses were conducted in a secondary wood area within the Campus of Campinas State University - UNICAMP (22o49'15S, 47o04'08W) in the municipality of Campinas (Brazil), from August 2003 to June 2004, to analyze the composition of the local carrion visiting and colonizing invertebrate fauna. Four laboratory mouse carcasses (Mus musculus) and four rat carcasses (Rattus norvegicus) were exposed in each season, during the set period. All the carcasses were placed in an iron-mesh cage, which was adequate to collect adult and immature insects. In the course of the decomposition of the 32 rodent carcasses, 6514 specimens (820 adults and 5694 immatures) of 53 arthropod species from the families Sarcophagidae, Calliphoridae, Muscidae, Fanniidae, Syrphidae, Richardiidae, Sepsidae, Micropezidae, Otitidae, Drosophilidae, Phoridae, Dolichopodidae, Anthomyiidae, Asilidae and Lauxaniidae (Diptera), Formicidae, Ichneumonidae, Encyrtidae e Apidae (Hymenoptera), Staphylinidae (Coleoptera) and Gonyleptidae (Opiliones) were collected. The most abundant species breeding on the carcasses were Lucilia eximia (Wiedemann, 1819) (Diptera: Calliphoridae) and some Sarcophagidae species, such as Peckia (Pattonella) intermutans (Walker, 1861) and Sarcophaga (Liopygia) ruficornis (Fabricius, 1794), which are rarely seen breeding on carcasses of large animals. This behavior can suggest a specialization of these species in colonizing small carcasses, possibly an attempt to avoid competition with other species of necrophagous Diptera in carcasses of large animals

Insectos de importancia forense en cadáveres de ratas,Carabobo - Venezuela

Objectives: To determine the composition of entomological fauna associated to rat carcass, in that allows to establish the species of forensic importance in Carabobo, Venezuela. Materials and methods: Insects were studied in nine carcasses of laboratory rats’. Every day each rat (carcass and trays with soil substrate) was picked up in order to obtain associated fauna. With the abundance data indexes of diversity and evenness were calculated, and the principal component analysis was used. Results: 13 590 insects were collected; 14,8% from the carcasses and 85,2% from the trays. Diptera were the most abundant insects (94,2%), followed by Coleoptera and Hymenoptera. Most important Diptera species were: Calliphoridae: Lucilia cluvia (Walker), Chrysomya albiceps (Wiedemann), and C. megacephala (Fabricius), and Muscidae: Musca domestica Linnaeus. Some Coleoptera were found, such as Dermestes ater DeGeer (Dermestidae), and Staphylinidae. Conclusions: Evenness and diversity were low, because the greater species abundance, and the poor sensitivity of diversity indexes was due to the presence of unusual species. Species succession was also observed; L. cluvia was found during the first days, followed by C. albiceps and C. megacephala. We recommend continuing with this type of studies, so they may be used as a tool in forensic medicine practice in Venezuela.

Synanthropy of Muscidae (Diptera) in the city of Valdivia, Chile

The objective of the present study was to determine the index of synanthropy of adults of Muscidae species collected in Valdivia, Chile (39°48'S; 73°15'W). The flies were collected monthly between September 1996 and August 1997 at three different locations, representing urban, rural and natural environments. Rat carcasses, chicken viscera, and fish viscera were used as bait. Six species of Muscidae were collected: Psilochaeta chalybea (Wiedemann) was dominant in urban and rural habitats, being eusynanthropic. The second species in importance was Hydrotaea acuta (Stein), being hemisynanthropic and more abundant in the natural environment. Ophyra ignava (Harris) was another species captured in relatively large numbers, and showing eusynanthropic characteristic. The remaining three species, Musca domestica L., Palpibracus valdiviensis (Couri & Pamplona), and Mu scina stabulans (Fallén) were captured in low numbers. In addition to the indexes of synanthropy, monthly abundances were determined and discussed, as well as the efficiency of the different baits used to collect the flies. The medical and sanitary importance of the flies was also assessed.

The activity of Sand Goannas Varanus gouldii and their interaction with reintroduced Greater Stick-nest Rats Leporillus conditor

The activity pattern of the Sand Goanna Varanus gouldii in northern South Australia was estimated by radio telemetryduring the summer months. Individuals were located within the Arid Recovery Reserve where introduced European Rabbits Oryctolagus cunniculus, Feral Cats Felis catus and European Foxes Vulpes vulpes were removed. Interaction between the re-introduced Greater Stick-nest Rat Leporillus conditor and the Sand Goanna, a potential significant predator in the absence of cats and foxes, was examined. Mean activity area for Sand Goannas was 5.9 ha (�1.0, n = 9), and their summer activity was concentrated on sand dunes rather than the adjacent inter-dunal swales. Tracks of Sand Goannas were found more often around Greater Stick-nest Rat nests than control sites. However, Sand Goanna predation on re-introduced Greater Stick-nest Rats could not be confirmed and most deaths of radio-collared Greater Stick-nest Rats coincided with a period of exceptionally high maximum temperatures and were probably due to heat and dehydration. Sand Goannas scavenged Greater Stick-nest Rat carcasses, and analysis of scats and stomach material revealed that although invertebrates were the most common prey item, mammal material (hair and bones) was present in 20% of scats.

Effect of Sheep and Chicken Antibodies to Rat Adipocytes Plasma Membranes on Rat Carcass Fat

Polyclonal anti-sera were collected from sheep and chicken immunized with adipocytes plasma membranes. Thirty two male wistar rats, weighing 185-215 grams, were divided randomly into 4 groups (trial 1: control group and treat group, trial 2: control group and treat group), with 8 rats in each group. The experiment lasted for 7 weeks. Trial one: The control group received four consecutive daily intraperitoneal injections of 1ml of sheep normal sera. The same 4 day daily dose of group sheep anti-rats sera adipocyte plasma membrane anti-sera was administered to the treat group. The results showed that the treatment for treat group increased body weight by 6.35% (p<0.05) and food intake by 6.85%, and improved food conversion efficiency (Food intake/gain) by 45.00% (p<0.05). Periernal, epididymal and omental adipose deposit weights were decreased by 23.92% (p<0.05), 34.45% (p<0.05) and 0.98% respectively, while total fat content decreased by 20.92%. Trial two: The control group received four consecutive daily intraperitoneal injections of 1 ml of chicken normal sera, the results of injections of chicken anti-rats sera adipocyte plasma membrane antis-era administered to the treat group indicated that chicken anti-rats adipocyte plasma membranes immunization had an disadvantageous effect on the growth of the wistar rats by the end of 7th wk, compared with the control group. The immunized group decreased in total weight by 40 gram (p<0.05) an averagely and in food intake noticeably (p<0.01). The deposition of fat and the rates of TG and FFA in serum had no statistical significance. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 8 : 1177-1182)

The Position of Rumenic Acid on Triacylglycerols Alters Its Bioavailability in Rats

The metabolic fate of rumenic acid (9cis,11trans-octadecenoic acid) related to its position on the glycerol moiety has not yet been studied. In the present work, synthetic triacylglycerols (TAG) esterified with oleic and rumenic acids were prepared. Rats were force-fed synthetic dioleyl monorumenyl glycerol with (14)C labeled rumenic acid in the internal (sn-2) or in the external position (sn-1 or sn-3). Rats were then placed in metabolic cages for 16 h. At the end of the experiment, the radioactivity in tissues, carcass and expired CO(2) was measured. Rumenic acid that was esterified at the external positions on the TAG was better absorbed and oxidized to a greater extent than when esterified at the internal position. The fatty acid from the 2-TAG form was also better incorporated into the rat carcass. In the liver, rumenic acid appeared mainly in TAG (50%) and to a lesser extent in phospholipids (33%) whatever its dietary form. Moreover, analyses of lipids from Camembert cheese and butter revealed that rumenic acid was located mainly on the sn-1 or sn-3 positions (74%). Taken together, these data suggest that rumenic acid from dairy fat may be well absorbed and used extensively for energy production.