Comparative evaluation of methods for studying the degree of assimilation of feed by animals

Relevance. The activity of the digestive organs is largely determined by the feeding regime, in particular, the frequency, timeliness, and the order of feeding the feed. The digestibility of nutrients is influenced by the preparation of feed for feeding, which facilitates mechanical processing in the digestive tract and the action of digestive enzymes. Against the background of a decrease in the natural resistance of the animal body, an important aspect is the use of mineral supplements and the enrichment of diets with biologically active substances that increase the nutritional value and the degree of assimilation of feed by animals. The aim of the work was a comparative assessment of methods for studying the degree of assimilation of feed by animals.Methods. To determine the degree of food assimilation, 2 drops of isotonic (0.9%) sodium chloride solution and a small amount of intestinal contents were applied to a glass slide, a thin smear was prepared, dried in air for 30 min, and large particles were removed. The preparations were fixed for 15 min with 96% ethyl alcohol, then 3–5 drops of a 1.0% aqueous solution of methylene blue, Lugol, Sudan III were applied. Along with the indicated conventional methods, we tested a method for preparing preparations using fixation in vapors of a 25.0% solution of glutaraldehyde for 30–40 minutes, in vapors of a 1.0% aqueous solution of osmium tetroxide.Results. The kinetics of the formation of intestinal microbiocenoses is characterized by a decrease in the number of lactobacilli and an increase in the number of pathogenic and opportunistic bacteria. In a comparative assessment of the preparation methods, the advantage of microscopic research methods is the possibility of a detailed study of the contents, the degree of assimilation of feed components in the gastrointestinal tract, and a visual assessment of the state of the intestinal microflora. The advantage of the method for preparing preparations with the use of vapor fixation of a 25.0% solution of glutaraldehyde and osmium tetroxide is the possibility of visualizing the formation of monospecific and polyspecies biofilms by optical and scanning electron microscopy. The preparations were sufficiently contrasting, there were no artifacts, bacteria and fungi stained brown, which made it possible to count even pinpoint colonies using a magnifying glass or an optical microscope. The easily digestible feed results in a low fecal yield and a stable consistency. The use of functional food “Pristine Gold Vet” in the nutrition of dogs and fur-bearing animals made it possible to increase the absorption of nutrients by 18,1% and 15,3%.

Tauco, Perpaduan Rasa yang Eksotis

Abstrak Makanan merupakan salah satu cara untuk meningkatkan Pariwisata di suatu daerah. Banyak wisatawan yang datang ke suatu daerah karena ingin mencoba makanan khas dari daerah tersebut. Indonesia kaya akan makanan khas dari tiap daerah, salah satunya adalah Tauco. Tauco merupakan ikonik dari Kota Cianjur. Tauco adalah makanan berfermentasi yang berfungsi sebagai bumbu dalam masakan. Dengan seiring jaman, bangsa Cina yang tinggal dan menetap mulai memperkenalkan Tauco kepada masyarakat setempat. Tetapi karena rasa asli Tauco kurang digemari oleh masyarakat setempat, maka rasa Tauco mulai mengalami perubahan untuk menyesuaikan dengan rasa yang dikenal oleh masyarakat setempat. Perlu untuk mengetahui jejak sejarah dari tiap makanan tradisional agar kita dapat menjaga dan melestarikan serta memperkenalkan ke dunia luar. Tujuan dari penelitian ini adalah untuk mengetahui sejarah dari Tauco, cara pembuatan tauco dan bagaimana eksistesinya saat ini. Metode penelitian yang digunakan adalah kualitatif dan melakukan pengumpulan data dengan cara wawancara, kuisioner dan studi literatur. Nara sumber adalah pemilik pabrik tauco yang merupakan keturunan keempat dari generasinya dan pemilik rumah makan yang sudah berkecimpung di dunia restoran selama 68 tahun. Sedangkan untuk responden kuisioner didapatkan 100 orang yang berasal dari berbagai kota. Hasil dari penelitian ini didapatkan bahwa Tauco dibawa pertama kali ke kota Cianjur oleh bangsa Tiongkok (China) pada masa penjajahan Belanda yang kemudian berasimilasi dengan rasa lokal sehingga dapat diterima dan disenangi oleh masyarakat. Cara pembuatan masih menggunakan cara tradisional, terutama proses pengeringan yang masih menggunakan sinar matahari, menggunakan kendi tanah liat yang sudah berumur ratusan tahun dan cara pemasakan yang manggunakan kayu bakar. Sedangkan eksistensi tauco sampai saat ini masih banyak berada di generasi tua. Karenanya disarankan untuk lebih memperkenalkan masakan tradisional seperti tauco kepada generasi muda, bisa melalui seminar atau pengetahuan tambahan yang diberikan di sekolah. Agar generasi muda dapat mengenal, menyukai dan ikut menjaga masakan khas daerahnya. Keyword : Tauco, Makanan Khas, Asimilasi Abstract Food is one way to increase tourism. Because sometimes tourists come to specific area because they want to try special foods from that area. Indonesia is rich in specialties from each region, one of which is Tauco. Tauco is an iconic of Cianjur. Tauco is a fermented food that serves as a spice in cooking. Derived from soybeans through a long process because it still uses the traditional method so that it becomes a cooking spice that can be used to cook various kinds of food ingredients such as fish, vegetables, chicken, and many more. The purpose of this research is to know the history of Tauco, how to make tauco and how it exists today. The research method used is qualitative and performs data collection by interviews, questionnaires and literature studies. The resource person is a tauco factory owner who is the fourth descendant of his generation and a restaurant owner who has been in the restaurant world for 68 years. Meanwhile, for the questionnaire respondents, it was found that 100 people came from various cities. The results of this study found that Tauco was first brought to the city of Cianjur by the Chinese during the Dutch colonial period which then assimilated it with a local taste so that it could be accepted and liked by the community. The manufacturing method still uses traditional methods, especially the drying process which still uses sunlight, using a clay jug that is hundreds of years old and the cooking method using firewood. Meanwhile, the existence of tauco is still in the older generation. Therefore, it is advisable to introduce more traditional dishes such as tauco to the younger generation, through seminars or additional knowledge given at school. So that the younger generation can get to know, like and take part in preserving their regional specialties. Keyword: Tauco, Specialty Food, Assimilation

Numerical model of the spatio-temporal dynamics in a water strider group

The water strider group demonstrates a very complex dynamics consisting of competition for the food items, territoriality and aggression to the conspecific individuals, escaping from the predators, etc. The situation is even more complex due to the presence of different instars, which in most water strider species live in the same habitat and occupy the same niche. The presented swarm model of water striders demonstrates the realistic population dynamics. For the swarm formation in the model, attraction and repulsion forces were used. Animal motion in the model takes into account inertia and kinetic energy dissipation effects. The model includes three different rates related to the growth of individuals: food appearance rate, food assimilation rate, and stored energy loss rate. The results of our modeling show that the size distribution of individuals seems to be an adequate measure for population status, and it has a characteristic shape for different model parameter combinations. Distribution of the distances between nearest neighbors is other important measure of the population density and its dynamics. Parameters of the model can be tuned in such a way, that the shape of both distributions in a steady phase coincides with that shape observed in a natural population, which helps to understand the factors leading to particular momentary distribution of both parameters (size and distance) in the population. From this point of view, the model can predict how both distributions can further develop from certain state depending on particular combination of factors.

Copepod Production in Warm, Oil Polluted Environment: A Laboratory Investigation of Temora stylifera (Dana, 1849) Adapted to the Gulf of Guinea

Recent studies suggests that sea surface warming, evidently caused by greenhouse gas emissions, magnifies the toxicity of petroleum hydrocarbons on marine copepods. We assessed this understanding using Temora stylifera, a calanoid copepod common in the Atlantic Ocean and its surrounding waters, as a case study. The copepod was exposed to moderate (0.2 μg.l-1) and high levels (2.0 μg.l-1) of pyrene under three warming scenarios: (i) a no warming control at 28 °C, the surface temperature of the Gulf of Guinea during stable hydrographic period, (ii) moderate warming (+2 °C) and (iii) severe warming (+4 °C) above the control. Food ingestion rate of the copepod increased with warming without significant effect from the pollutant. Feacal pellet production rate (FP) increased by about 86% when the animal was exposed to moderate warming and pyrene at the same time, signifying reduced assimilation of food ingested in these conditions. Lowest FP (3.5 ± 1.1 copepod-1.day-1) indicating increased food assimilation occurred when the stressors were presented either alone or together. Egg production rate and efficiency of the copepod were impacted by only warming, decreasing by ≈60% under both warming scenarios, consistent with previous observations. Mortality rate increased by ≈ 40 % when pyrene pollution was elevated from nought to the highest level. It did not change significantly with temperature, suggesting warming did not exacerbate the lethal effect of pyrene to T. stylifera. These results are contrary to observations on other copepods and highlight the unique responses of Temora to sea surface warming and petroleum pollution.

Evaluation of African Maize Cultivars for Resistance to Fall Armyworm Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) Larvae

The fall armyworm (FAW) has recently invaded and become an important pest of maize in Africa causing yield losses reaching up to a third of maize annual production. The present study evaluated different aspects of resistance of six maize cultivars, cropped by farmers in Kenya, to FAW larvae feeding under laboratory and field conditions. We assessed the arrestment and feeding of FAW neonate larvae in no-choice and choice experiments, development of larvae-pupae, food assimilation under laboratory conditions and plant damage in a field experiment. We did not find complete resistance to FAW feeding in the evaluated maize cultivars, but we detected differences in acceptance and preference when FAW larvae were given a choice between certain cultivars. Moreover, the smallest pupal weight and the lowest growth index were found on ’SC Duma 43′ leaves, which suggests an effect of antibiosis of this maize hybrid against FAW larvae. In contrast, the highest growth index was recorded on ‘Rachar’ and the greatest pupal weight was found on ‘Nyamula’ and ‘Rachar’. The density of trichomes on the leaves of these maize cultivars seems not to be directly related to the preference of neonates for feeding. Plant damage scores were not statistically different between cultivars in the field neither under natural nor artificial infestation. However, plant damage scores in ‘Nyamula’ and ‘Jowi’ tended to be lower in the two last samplings of the season compared to the two initial samplings under artificial infestation. Our study provides insight into FAW larval preferences and performance on some African maize cultivars, showing that there are differences between cultivars in these variables; but high levels of resistance to larvae feeding were not found.

Self-Selection of Agricultural By-Products and Food Ingredients by Tenebrio molitor (Coleoptera: Tenebrionidae) and Impact on Food Utilization and Nutrient Intake

Nutrient self-selection was used to determine optimal intake ratios of macro-nutrients by Tenebrio molitor L. larvae. Self-selection experiments consisted of 9 combinations (treatments) of 8 ingredients, from a total of 20 choices, radially distributed in a multiple-choice arena presented to groups of 100 T. molitor larvae (12th–13th instar). Larvae freely selected and feed on the pelletized ingredients for a period of 21 days at 27 °C, 75% RH, and dark conditions. Consumption (g) of each ingredient, larval live weight gained (mg), and frass production were recorded and used to calculate food assimilation and efficiency of conversion of ingested food. The macro-nutrient intake ratios were 0.06 ± 0.03, 0.23 ± 0.01, and 0.71 ± 0.03 for lipid, protein, and carbohydrate, respectively on the best performing treatments. The intake of neutral detergent fiber negatively impacted food assimilation, food conversion and biomass gain. Food assimilation, food conversion, and biomass gain were significantly impacted by the intake of carbohydrate in a positive way. Cabbage, potato, wheat bran, rice bran (whole and defatted), corn dry distillers’ grain, spent brewery dry grain, canola meal and sunflower meal were considered suitable as T. molitor diets ingredients based on their relative consumption percentages (over 10%) within treatment.

Application of Effective Day Degrees in the Assessment of Stable Isotope Patterns in Developing Seahorses under Different Temperatures

Relations between nutrient assimilation and growth rate in fishes may vary with abiotic factors such as temperature. The effects of feeding status, ontogeny and temperature regimes (15, 18 and 21 °C) on stable isotope (δ13C and δ15N) patterns were assessed in juveniles of the seahorse Hippocampus guttulatus. The use of effective day degrees (D°eff), day degrees (D°) and chronological time (age) were compared as development progress indices. Newborn seahorses were maintained at three temperature levels both deprived of food (5 days) or fed (30 days) on copepods or/and Artemia. Isotopic signatures in fed seahorses clearly differed from those in unfed juveniles. Temperature had a significant effect on δ13C values in fed juveniles throughout the experimental period. δ15N values also varied significantly with age, but not with temperature level. Faster growth and food assimilation in seahorses held at 18 and 21 °C were supported by faster variations in isotopic values. Our findings demonstrate that effective day degrees should be preferred over chronological time as index of developmental progress in temperature fluctuating scenarios or for comparative studios.

Application of Effective Day Degrees in the Assessment of Stable Isotope Patterns in Developing Seahorses under Different Temperatures

Relations between nutrient assimilation and growth rate in fishes may vary with abiotic factors such as temperature. The effects of feeding status, ontogeny and temperature regimes (15, 18 and 21 °C) on stable isotope (δ13C and δ15N) patterns were assayed and modelled in juveniles of the seahorse Hippocampus guttulatus. The use of effective day degrees (D°eff) and chronological time (age) were compared as development progress indices. Newborn seahorses were maintained at three temperature levels both deprived of food (5 days) or fed (30 days) on copepods or/and Artemia. Isotopic signatures in fed seahorses clearly differed from those in unfed juveniles. Temperature had a significant effect on δ13C values in fed juveniles throughout the experimental period. δ15N values also varied significantly with age, but not with temperature level. Faster growth and food assimilation in seahorses held at 18 and 21 °C were supported by faster variations in isotopic values. Our findings demonstrate that effective day degrees should be preferred over chronological time as index of developmental progress in temperature fluctuating scenarios or for comparative studies.

Investigating food assimilation in a carnivorous teleost by stable isotopes analysis: the case of ribbonfish off south-east Brazil

This study verifies the food assimilation of a carnivorous teleost in different timescales (weeks vs months) and evaluates how it uses the food sources. The target species is the adult ribbonfish, Trichiurus lepturus, a voracious teleost caught in commercial fisheries off south-east Brazil (21°S–22°S). The isotope models indicated Chirocentrodon bleekerianus as the main food in the ribbonfish diet in the last weeks (liver: 38.5%; 95% credible intervals: 3.4–73.9%) and last months (muscle: 36.2%; 95% credible intervals: 3.4–68.7%). The contribution of other food sources ranges from 10–16% (liver) and from 10–20% (muscle). Food assimilation remains similar at different timescales. The isotope models suggested a strong and long-lasting association of the adult females of ribbonfish with coastal waters along the study area.

Biomagnification of methylmercury in a marine plankton ecosystem

<p>Methylmercury is greatly bioconcentrated and biomagnified in marine plankton ecosystems, and these communities form the basis of marine food webs. Therefore, evaluating the potential exposure of methylmercury to higher trophic levels, including humans, requires a better understanding of its distribution in the ocean and the factors that control its biomagnification. In this study, a coupled physical/ecological model was used to simulate the trophic transfer of monomethylmercury (MMHg) in a marine plankton ecosystem. The model includes phytoplankton, a microbial community, herbivorous zooplankton (HZ), and carnivorous zooplankton (CZ). The model captured both shorter food chains in oligotrophic regions, with small HZ feeding on small phytoplankton, and longer chains in higher nutrient conditions, with larger HZ feeding on larger phytoplankton and larger CZ feeding on larger HZ. In the model, trophic dilution occurred in the food webs that involved small zooplankton, as the grazing fluxes of small zooplankton were insufficient to accumulate more MMHg in themselves than in their prey. The model suggested that biomagnification was more prominent in large zooplankton and that the microbial community played an important role in the trophic transfer of MMHg. Sensitivity analyses showed that with increasing body size, the sensitivity of the trophic magnification ratio to grazing, mortality rates, and food assimilation efficiency (AE<sub>C</sub>) increased, while the sensitivity to excretion rates decreased. More predation or a longer zooplankton lifespan may lead to more prominent biomagnification, especially for large species. Because lower AE<sub>C</sub> resulted in more predation, modeled ratios of MMHg concentrations between large CZ and HZ doubled when the AE<sub>C</sub> decreased from 40% to 10%. This suggested that the biomagnification of large zooplankton was particularly sensitive to food assimilation efficiency.</p>