Stomach Content Analysis

SUMMARY: Chapter 7, in Renfrew & Bahn's textbook (Archaeology: Theories, Methods, and Practice), covers how to assess past subsistence and diet, including plant food (e.g., macro- and microbotanical remains; plant residues; seasonality; domestication), animal resources (e.g., macro-faunal remains; age, sex, and seasonality; domestication; small fauna; types of exploitation), and assessing diet from human remains (e.g., stomach contents; feces; teeth; isotopic methods; bone collagen).  A small case study is placed at the end of this ppt. lecture, emphasizing some aspects of subsistence.  In my view, this is one of the best college textbooks available, and is invaluable for students, archaeologists, and the public in general, to obtain a top notch overview of approaching and interpreting the archaeological record. UPDATED May 2023.

El Tiburón Come perro o Madre cazón, Carcharhinus leucas de distribución mundial se encuentra presente en aguas ecuatorianas y es objeto de una pesquería artesanal dirigida a lo largo de la costa continental. Se analizaron 83 ejemplares (53 machos y 30 hembras). Machos: 208 y 309
cm (LT); hembras: 199 y 350 cm (LT). Proporción de sexos 1H:1.7M, se sugiere una segregación por sexos. La fecundidad varió desde 2 hasta 12 embriones por hembra, con tallas de 59 a 82 cm LT. El IIR dentro del análisis de contenido estomacal determinó: peces óseos (80.41%), peces cartilaginosos (12.53%), reptiles (5.94%) y moluscos (1.12%). C. leucas, es una de las especies de tiburón que se aprovecha integramente (carne, aletas, hígado, embriones, vísceras y mandíbula). La pesquería de esta especie esta soportada por adultos con un 96% de la captura total. Se sugieren recomendaciones para establecer su manejo y conservación.

This study presents information on the diet of two shark species, Carcharhinus leucas and Galeocerdo cuvier, that inhabit the southeastern Pacific Ocean. The stomachs were collected from October 2003 to July 2005 in Ecuador. Stomachs of 41 C. leucas and six
G. cuvier were analyzed. According to the index of relative importance (%IRI), the most important prey for C. leucas were fishes: family Ophichthidae (13.41%), Tylosurus pacificus (9.79%), Katsuwonus pelamis (4.54%), and fish remains (44.81%). G. cuvier, for its part, consumed squids: Ancistrocheirus lesueuri (45.14%), Pholidoteuthis boschmaii (7.81%), and Octopoteuthis spp. (5.17%), as well as turtles: Caretta caretta (9.7%), Lepidochelys cf. kempii (5%), and turtle remains (16.5%). The results show that C. leucas (trophic level, ITR; 4.32 ± 0.13) and G. cuvier (ITR; 4.26 ± 0.09) are tertiary consumers, occupying high positions in the food chain, but also are generalist predators that feed on a variety of prey. The high frequency of sea turtles in the stomachs of G. cuvier (>300 cm) suggests that this shark species is an important predator of turtles, which are commonly found along the southeastern Pacific coasts

The food and feeding habits of some fish fauna in Anwai stream were investigated. Fish samples (160 individual fish in 19 species) were collected using combination of traps, gill nets of various mesh sizes and baited hooks and lines in the three zones (upper, middle and lower reaches) of the stream. Stomach content analysis was carried out using frequency of occurrence, numerical analysis and volumetric analysis. It was observed that Hemichromis Fasciatus competed with fish species of commercial importance viz Tilapia zilli, Christinus guentheri and Oreochromis niloticus for major food items (100 F% of blue green algae, green algae and diatom). Feeding intensity (absolute importance index) of Hemichromini bimasculatus (700) and O. niloticus (801) remain relatively higher than that of the other fish species during the study.

Climate change is expected to strongly impact Alaskan (USA) marine ecosystems, particularly those of the northern Bering Sea. To understand how climate change may alter predator demand for prey resources, we quantified the relationship between temperature and allometric rates of prey consumption for 3 major groundfish predators: walleye pollock (Gadus chalcogrammus), Pacific cod (Gadus macrocephalus), and arrowtooth flounder (Atheresthes stomias). We contrasted regional patterns in foraging rates of more than 120 thousand fish collected annually from 1981-2011 from eastern Bering Sea (EBS), Gulf of Alaska (GOA), and Aleutian Islands (AI). From field observations, we estimate that juveniles and adults of each species eat 1.15–3.94 and 0.84 -3.13 times their body weight (BW) per year, respectively (i.e., 0.2%-1.2% BW d-1) with arrowtooth from in all 3 regions and adult EBS Pacific cod exhibiting the highest rates. If historical patterns signify future conditions, we estimate that a 2 oC projected increase in water temperature would cause 26% and 14% increases in daily rations of adult EBS pollock and Pacific cod, respectively, whereas we predict a 37% decline in the daily rations of EBS arrowtooth. Similarly, we predict that GOA pollock, Pacific cod and arrowtooth rations would increase markedly (70%, 34%, and 65%, respectively). Although daily ration of AI arrowtooth may increase 31%, our models predict 41% and 3% declines in AI pollock and Pacific cod rations, respectively. These results portend (sometimes counterintuitive) region- and species-specific shifts in Alaska groundfish predator foraging rates and trophodynamic interactions concomitant with climate change.

We analysed the stomach contents of 69 silky sharks Carcharhinus falciformis, 44 blacktip sharks Carcharhinus limbatus and 24 whitenose sharks Nasolamia velox caught in the Ecuadorian Pacific from August 2003 to December 2004. Prey included bony fishes, elasmobranchs, molluscs, crustaceans and turtles, with bony fishes being the most important to the diets of all three sharks, suggesting they are piscivorous predators. Based on the index of relative importance, the C. falciformis diet includes Thunnus albacares, Thunnus sp. and Auxis thazard, as well as some squid, fish and turtles. Similarly, the C. limbatus diet was dominated by T. albacares, Exocoetus monocirrhus, A. thazard, Katsuwonus pelamis, members of the Ophichthidae family and other elasmobranchs. Meanwhile, N. velox consumed mainly Dosidicus gigas, Larimus argenteus, Cynoscion sp. and Lophiodes spilurus. There is little competition for food between these tertiary carnivores: C. limbatus prefers prey from coastal-oceanic h...

The dusky grouper (Mycteroperca marginata) is a marine species usually associated with rocky bottoms and reefs. The present work investigated the diet and feeding strategy of a dusky grouper population inhabiting a 4.5 km long pair of rocky jetties located in the mouth of Patos Lagoon estuary. No prior research has been conducted in such man-made habitat and the current study provides a basis for comparative studies on the diet of the dusky grouper populations inhabiting natural vs. man-made rocky habitats. Similarly with previous studies on natural substrates, crabs and fishes were the main food categories consumed (%IRI = 85.1 and %IRI = 12.6, respectively), whereas shrimps and mollusks had lower importance in the diet (%IRI = 1.9 and 0.4, respectively). As previously reported for dusky grouper populations inhabiting reefs and rocky bottoms, the present work revealed conspicuous size related dietary shifts. Blue crabs and fishes become increasingly important food items in the diet of larger individuals (> 500 mm, TL). Finally, it was found that the studied dusky population has a generalist feeding strategy with a high between-individual variation in prey consumption. Such strategy remained similar across the size increment of the species. Our findings suggest that man-made rocky substrates provide suitable feeding grounds for the dusky grouper in southern Brazil and could be used as an additional tool in the conservation efforts of this endangered species.

Studies on feeding ecology provide information of great importance to the understanding of aquatic ecosystems. However, these studies usually require the sacrifice of animals. In view of this problem, the presently reported study aims to evaluate the effectiveness and applicability of the gastric lavage method for small catfishes. There was no mortality recorded for the 80 specimens of Rhamdia quelen (Quoy et Gaimard, 1824) and after recovery from anaesthesia all fish presented a normal swimming pattern. With the gastric lavage method we were able to retrieve 71.4% of the stomach contents of 34 specimens of Pimelodella pappenheimi Ahl, 1925. These results serve as a stimulus for studies prioritizing non-lethal techniques. These methods would ensure greater knowledge about ecology and conservation of smaller fishes, especially to populations of small and rare species that are the most endangered in freshwater systems.

All sturgeon species currently living in the Danube River are either critically endangered or at the edge of extinction. Sturgeons are mainly benthic feeders, with a diet of molluscs, crustaceans, and small fishes. During the last two decades, we have seen a significant change in the species composition of benthic invertebrates in the Danube River as a result of anthropogenic impacts-hydrological and habitat modifications, introduction of alien and invasive species. The aim of this study was to investigate the food composition and the importance of different prey taxa, and to describe the feeding strategies of young sturgeons along the Bulgarian section of the Danube River. From June to August 2019, the stomach contents of 61 fish specimens from the species Acipenser stellatus, A. ruthenus, A. gueldenstaedtii were collected using gastric lavage. It was found that Obesogammarus obesus (Amphipoda) prevails in the diet of young of the year (YOY) A. stellatus and A. gueldenstaedtii, while Corbicula fluminea (Bivalvia) was the main food item of A. ruthenus. Chironomidae larvae also had high occurrences in the diet of all sturgeon species. For the YOY specimens up to 35 cm total length, nearly 94% of prey items belonged to O. obesus and diet overlap was observed. Improved knowledge about the diet of the young sturgeons could lead to the determination of the species' major feeding habitats in the Danube River, providing crucial information for their protection and restoration.

The botanical composition of the European roe deer diet in the radioactively contaminated forest ecosystems of Zhytomirske Polesie of the Ukraine was investigated. Deer were caught monthly over a two–year period on three plots in forest habitats typical for Zhytomirske Polesie (fresh and moist mixed coniferous forests and mixed broadleaved forests). An analysis of the stomach contents of hunted deer showed that they consumed leafy as well as leafless stems, grasses, fruits and mushrooms

depending on the season and availability of forest plants. Each season was characterized by one major dietary component. In the spring, the main component of the deer diet was the stems of woody plants. 44 species of vascular plants (3% of the natural flora of the region) were identified in the roe deer diet including 41 species of Magnoliophyta, of which 34 species of Magnoliopsida and 7 species of Liliopsida, 2 species of Polipodiophyta and one species of Pinophyta. Species such as aspen (Populus tremula), oak (Quercus robur), blackberry (Rubus nessensis) and bilberry (Vaccinium myrtillus) were consumed year-round.

Stomach contents of a male 120cm long Palm Civet (Paradoxurus hermophroditus) described from Satkosia Tiger Reserve, Odisha. The ingested items are (1) seeds of  ‘Kendu’ fruits (Diospyros melanoxylon): 7 nos.from at least two fruits, (2) some fleshy white root: 3 pieces, each about 1cm cube; (3) Eublepharis hardwickii (gecko): 1 number, 5cm long; (4) portions of 2 scorpions, 15cm and 8cm long; (5) centipedes: 2 nos.- portions of a small and a large specimen; (6) Viper snake: 1 no. 40cm TBL, 36cm SV; (7) Typhlops: 3 nos., 14.5, 7.5 and 7.0cm length; and (8) cockroach: 1no. complete wings and only portions of abdomen exoskeleton. Civet has been described as very useful animal to have around human habitations.

Microinvasive methods are widely used in studies of rare and endangered animals. All sturgeon species currently living in the Danube River are either critically endangered or at the edge of extinction. The reasons for this are complex, but one of the possible is changes in food resources. Although sturgeons have been studied on a systematic and zoogeographical point of view, the diet of sturgeons in the Lower Danube waters is quite unknown. The aim of the present study is testing application of non lethal methodology for investigation of the diet composition of the sturgeons.
During a three months sampling (from June to August 2019), 56 specimens [N – 56; mean total length (TL) - 367 mm; range: 180 – 580 mm; mean weigh (W) - 274,5 g; range: 29 – 1145 g] from species Acipenser gueldenstaedtii, A. stellatus and A. ruthenus were collected from Danube River near the village Vetren. The study has tested a methodology for examination of gastric content of sturgeon species in field conditions using the gastric lavage method. Gastric lavage involves inserting a probe down the esophagus in to the stomach where water is flushed to induce regurgitation.
The results show that extraction of gastric contents was 91 % successful and more research is needed to test the efficiency of the method for specimens up to 45 grams. No lethal or negative effects were detected during the recovery period after the procedure.

Frog diets are influenced by multiple factors, including morphological constraints, habitat use, and seasonal variation in environmental conditions and food availability. This study combined stomach content analysis (SCA), stable isotope analysis (SIA), and estimates of prey availability to investigate the influence of body size and microhabitat use on seasonal variation of the trophic ecology of two sympatric hylids (Pseudis minuta and Scinax squalirostris). We evaluated two hypotheses: (1) the species with larger body and mouth sizes or broader use of microhabitats will have greater diet breadth, and (2) regardless of differences in morphological traits and microhabitat use, diet breadth of both species will be greater during the warmer of two periods. Pseudis minuta exhibited larger body size and mouth width and revealed broader use of microhabitats (mostly within and near major water bodies), whereas S. squalirostris had smaller body size and mouth gape and was found exclusively...

All sturgeon species currently living in the Danube River are either critically endangered or at the edge of extinction. Sturgeons are mainly benthic feeders, with a diet of molluscs, crustaceans, and small fishes. During the last two decades, we have seen a significant change in the species composition of benthic invertebrates in the Danube River as a result of anthropogenic impacts-hydrological and habitat modifications, introduction of alien and invasive species. The aim of this study was to investigate the food composition and the importance of different prey taxa, and to describe the feeding strategies of young sturgeons along the Bulgarian section of the Danube River. From June to August 2019, the stomach contents of 61 fish specimens from the species Acipenser stellatus, A. ruthenus, A. gueldenstaedtii were collected using gastric lavage. It was found that Obesogammarus obesus (Amphipoda) prevails in the diet of young of the year (YOY) A. stellatus and A. gueldenstaedtii, while Corbicula fluminea (Bivalvia) was the main food item of A. ruthenus. Chironomidae larvae also had high occurrences in the diet of all sturgeon species. For the YOY specimens up to 35 cm total length, nearly 94% of prey items belonged to O. obesus and diet overlap was observed. Improved knowledge about the diet of the young sturgeons could lead to the determination of the species' major feeding habitats in the Danube River, providing crucial information for their protection and restoration.

Acrylamide has several effects toxic and carcinogenic. The current project aimed at exploring the harmful effects of acrylamide on the structure of the stomach, cerebellum and testis in the albino rat, in an attempt to clarify its potential risk on the human health.
            The stomach, testis and cerebellum specimens were collected form fifty adult male albino rats. The animals were divided into two main groups. Group (I) was subdivided into 3 subgroups, control, Ia that received acrylamide in a dose of 25mg/kg/10days (P.O.) and Ib that received acrylamide in a dose of 25mg/kg/10days (I.P.). Group (II) was subdivided into 3 subgroups, control, IIa that received acrylamide in a dose of 50mg/kg/10days (P.O.) and IIb that received acrylamide in a dose of 50mg/kg/10days (I.P.).
At the end of the experiment, all rats were anesthetized using ether inhalation. Specimens from testis, cerebellum and stomach were extracted and processed for light and electron microscopic examination. For the light microscope serial sections 5-6µm thick obtained, stained with H&E (Testis, Cerebellum and Stomach); Feulgen stain (Testis) and silver stain (Modified Glees) (Cerebellum). Testicular specimens were studied with the Image analysis technique so as to assess cellular apoptosis. Moreover, DNA cytometry of the basal compartment of the testis was performed.
In the present work, it was found that the testis of the group treated with a dose of 25mg/kg/10days showed mild affection whether acrylamide was administered orally or intraperitoneally. On the other hand, the testis of the group treated with a dose of 50mg/kg/10days showed damage especially with the intraperitoneal administration in comparison to the oral treatment. This was in the form of degeneration of germ cells, numerous multinucleated giant cells with sloughed seminiferous epithelium, and vacuolations in-between the germ cells.
In addition, feulgen stain was performed to assess the effect of acrylamide on cellular apoptosis in the testis. It was clearly proved that acrylamide at a dose of 50mg/kg/10days showed increased apoptosis.
Image analysis of the feulgen stained sections was performed to evaluate the carcinogenicity of acrylamide on testis. It was found that acrylamide at a dose of 50mg/kg/10days showed increased abnormal DNA content in cells, which was considered a reliable marker for malignancy.
As regards effect of acrylamide on the cerebellum, it was concluded that the Purkinje cells were target cells to the acrylamide. Rats treated at a dose of 25mg/kg/10days showed that Purkinje cells somata appeared unaffected, while degeneration of Purkinje cells dendrites and corresponding axons were evident in the molecular and white matter respectively. Furthermore, rats treated with 50mg/kg/10days showed argyrophilic Purkinje cells somata and their dendrites were clearly evident in the Purkinje cell and molecular layers respectively. Also, Purkinje cell axon degeneration was observed in the white matter in the form of fragmented, linearly arrayed debris. The intraperitoneal treatment showed more damage as compared to the oral one.
The stomach of animals treated with acrylamide in a dose of 25mg/kg/10days showed no gastric affection, while there were mild degenerative changes and an apparent increase in mucous secreting cells in the group that received 50mg/kg/10days.
The present study pointed out the hazards of acrylamide and its possible effect on human health. Recommendations are necessary to decrease acrylamide level in different foods and ways to decrease acrylamide formation during preparation of the different foods should be advertised.