Feeding Competition Research Articles

Comparison of feeding behaviour characteristics between wild-caught and captive-reared Hippocampus kuda Bleeker

The yellow seahorse, Hippocampus kuda Bleeker, an ornamental and pharmaceutical fish, is being artificially cultivated due to the insufficient commercial supply of wild resources. However, the artificial breeding is difficult due to the limited biological knowledge. To improve the breeding technology of H. kuda, we compared the feeding behaviour of wild-caught group (GW) and captive-reared group (GC). The feeding behaviour of the wild and cultured H. kuda included six steps: searching, locking, alerting, catching, swallowing, and withdrawing. However, differences existed in their behavioural parameters. The GC of H. kuda had a longer reaction time, lower feeding rate, smaller food intake of live food and a shorter feeding distance than the GW. Furthermore, compared with those single state, H. kuda in groups have a shorter reaction time and higher feeding rate of single food, but a slower reaction to batch food. Most of the changes had no effect on the artificial breeding of seahorse. However, there are two points need to be adjusted in feeding management. Firstly, the seahorses will likely lack the behaviour of looking up for food, and only look down at the bottom. They may eat spoiled residual food and develop gastroenteritis diseases and death. Secondly, appropriate stocking density of seahorse and feeding frequency can maintain a feeding competition, which can reduce residual food and improve food utilisation.

Oral Processing of Three Guenon Species in Taï National Park, Côte d'Ivoire.

Three guenon species in Taï National Park frequently form and maintain stable polyspecific associations despite significant feeding competition. This dietary overlap provides an opportunity to examine how closely related and anatomically similar taxa process the same foods. Our research examines whether the oral-processing behaviors of these guenons differ when they consume the same foods. Methods: Data on oral-processing behavior were collected on one habituated group each of Cercopithecus campbelli, C. diana, and C. petaurista in Taï National Park, Côte d'Ivoire from January 2016 to December 2018. We recorded the frequency with which foods were introduced to the mouth (ingestive action) and the frequency with which foods were processed using incisors, canines, and postcanine teeth. Oral-processing profiles for species-specific plant foods, fungi, and invertebrates were compared using Monte Carlo resampling. We quantified oral-processing behavior during a total of 2316 five-minute focal periods. Diana monkeys use their incisors significantly more per ingestive action than Campbell's monkeys or Lesser spot-nosed guenons. Lesser spot-nosed guenons use their incisors more than Campbell's monkeys. Diana monkeys also use significantly more post-canine chews per ingestive action than Campbell's monkeys and Lesser spot-nosed guenons. Lesser spot-nosed guenons generally use fewer post-canine chews than Diana monkeys but more than Campbell's monkeys. Canine use during feeding was rare in all three taxa. The three study species use different oral-processing profiles when consuming the same foods. These results are intriguing given the overall similarity in dental and cranial anatomy in these taxa. The oral-processing profiles we report do not encompass the full dietary breadth of all species; however, the behavioral diversity demonstrated during consumption of the same foods suggests that insight into feeding behavior is more likely obtained by examining oral processing of individual foods rather than broad food categories. Furthermore, these results underscore that important variation in feeding behavior is not necessarily associated with morphological differences in dental or craniofacial anatomy.

Association patterns in a high-elevation chimpanzee community in Rwanda

Investment in social interaction and affiliative behaviour is often related to variation in sex-specific dispersal patterns among species but can also vary within species in response to local environmental conditions and feeding competition. Chimpanzee (Pan troglodytes) association patterns have been studied primarily in low and mid-elevation tropical forests. This study adds to our understanding of association patterns in chimpanzees by presenting the first data on association patterns in a high-elevation population at Nyungwe in equatorial Rwanda. Using data on co-occurrence in social parties (party association) and calculating gregariousness indices, we quantified levels of associations among age-sex classes relative to food (fruit) distribution and the presence of oestrous females. Overall, adult females in Nyungwe are less gregarious than males. Female but not male gregariousness increased when feeding on clumped foods, indicating that resource characteristics impact female association tendencies more intensely than males. Despite high elevation forests representing a habitat with relatively fewer fruit resources for chimpanzees, at an edge of range location, we found that gregariousness patterns were driven by similar factors as those in mid and low elevation chimpanzee populations.

Biological invasion: evidence from a tropical reservoir (Eleiyele, South West Nigeria

The encroachment of freshwater territories by invasive species is a global issue with its associated co-existence, displacement and facilitation of native species. The blackchin tilapia, Sarotherodon melanotheron is one of the most successful biological invasive species. Data on its apparent ecological consequences on native species are rare in Nigerian inland waters. Based on stomach contents analyses, diets, feeding strategies, and dietary niche breadths of two sympatric invasive S. melanotheron and native Nile tilapia Oreochromis niloticus populations in a tropical domestic water supply were assessed for possible convergence. Both species exhibited generalist feeding strategies subsisting mostly on algae but fish eggs and larvae were conspicuous preys of S. melanotheron. Dietary niche of S. melanotheron was wider than that of O. niloticus. Dietary niche overlap was high and significant between these sympatric species. These findings imply that competitive feeding interactions-including predations on vulnerable early life stages may potentially promote invasion success of S. melanotheron in Eleiyele Reservoir.

Agonistic behavior and feeding competition in the largest piranha species, Pygocentrus piraya, in a zoo

Agonistic behavior and feeding competition in the largest piranha species, Pygocentrus piraya, in a zoo

Follaje de leucaena (Leucaena esculenta) como reemplazo parcial de trigo en dietas para conejos de engorda: comportamiento productivo y rendimiento en canal

Thirty-nine weanling rabbits (New Zealand x English spot;30 days of age) were used in a four-week trial to evaluate the partial replacement of wheat grain for Leucaena leaf meal (Leucaena esculenta; LEU) on performance, carcass dressing percentage, and organ weights in fattening rabbits. Treatments consisted of partial replacement of wheat for 0%, 7.5%, or 15.0% of LEU in growing-finishing diet for fattening rabbits. Partial replacement of wheat grain with increasing levels of LEU did not influence (P>0.10) performance, carcass dressing percentage, and internal organs weights. It is concluded that this feeding strategy might contribute to reduce the food for feed competition while improving locally available forage resources for rabbit production in warm environments with multidimensional poverty.

Feeding Habits and Diet Overlap between Brown Trout Lineages from the Danube Basin of Croatia

Brown trout of non-native lineages have been stocked into Croatian streams and rivers primarily to meet angler demand. The diet of brown trout in the Black Sea Basin of Croatia is poorly understood, and there are no studies examining feeding competition between the Atlantic (AT) and Danube (DA) lineages of brown trout and their hybrids (HY). The aim of this study was to examine the natural diet of brown trout of both lineages and their hybrids and to compare feeding overlap. Canonical correspondence analysis was used to investigate the relationships between feeding habits of fish from different streams and of different genetic origin. The differences in variation of the consumed prey items were analysed by canonical variate analysis, and diet overlap was assessed by the Schoener index. The results indicate that stocked brown trout (AT) adapt rapidly to new habitat and food, as revealed by the consumption of a wide range of available food items and competition for food and space by taking on the feeding behaviour of wild native conspecifics. Diet overlap was also detected between brown trout of the DA and AT lineages. This study highlights the need to implement control measures to preserve and protect the native diversity of this species.

Food availability and male deference in the female‐dominant ring‐tailed lemur, Lemur catta

Female dominance, a trait common to some Malagasy lemurs, has been viewed as an adaptation that decreases intersexual feeding competition. A hypothesized relationship exists between male “deference” (male submission in the absence of female aggression) and food availability. Sauther (1993) suggested that male ring‐tailed lemurs at the Duke Lemur Center (Pereira et al., 1990) show more deference to females than do males in the wild owing to food abundance in captivity. To reexamine the link between food availability and male deference, we studied agonism and foraging in two nonwild ring‐tailed lemur (Lemur catta) populations: the Los Angeles Zoo and St. Catherines Island (SCI). On SCI, we collected data under two feeding conditions: Low Provisions (low food availability) and High Provisions (high food availability). As expected, male deference measures at our study sites were more similar to measures of deference from other studies of L. catta in captivity than in the wild. Additionally, the change at SCI from low to high food availability was associated with increased male deference to females. Interestingly, male proximity to females during foraging at this location did not notably change between the low to high food availability conditions, suggesting that males were food competitors of females just as often under both feeding conditions. The increase in male deference under conditions of high food availability on SCI was due to males withdrawing more rapidly from female approaches during agonistic interactions. Hence, where food is more abundant, male L. catta are more likely to show submission to females, which appears to be a self‐serving means of avoiding female aggression. Lemur males who are well‐fed appear less apt to risk female aggression to obtain resources than more nutritionally stressed males. Our results support the view of female dominance in lemurs as an adaptive evolutionary response to conditions of resource limitation.

Effects of Enrichment Type, Presentation and Social Status on Enrichment Use and Behavior of Sows-Part 2: Free Access Stall Feeding.

Simple SummaryThe Canadian pork industry is transitioning to group housing gestation. The Code of Practice for pigs recommends the provision of enrichment. Although straw is considered prime enrichment, it is perceived as a biosecurity risk and manure management issue; therefore, identifying other enrichment materials is needed to promote adequate welfare. Previously, our group examined the effects of four types of point-source enrichments in an Electronic Sow Feeding (ESF) system. This study is a continuation of our previous research applied in Free Access Stalls (FAS). Four treatments were studied: (1) Constant: constant provision of wood on chain; (2) Rotate: rotation of three enrichments (rope, straw, and wood on chain); (3) Stimulus: rotation of three enrichments with an associative stimulus (bell or whistle); and (4) Control: no enrichment. Contact with enrichment and time spent in different postures were measured using scan sampling. Skin lesions were scored, and salivary cortisol was measured in a subset of dominant and subordinate sows. Sows spent more time contacting straw compared to other types of enrichment. There was no difference in enrichment use between dominant and subordinate sows, no increase in cortisol concentrations in subordinates nor significant differences in aggression. In conclusion, sows preferred straw enrichment and FAS provided some protection against aggression and stress.Continuing with previous research by our group in an ESF system, four types of enrichment treatments were assessed in gestating sows housed in Free Access Stalls: (1) Constant: constant provision of wood on chain; (2) Rotate: rotation of rope, straw and wood; (3) Stimulus: rotation of enrichments with an acoustic cue; and (4) Control: no enrichment. Treatments had a 12 day-duration. Four groups (28 ± 2 sows) were studied from weeks 6 to 14 of gestation. Groups received all treatments in random order. Three dominant and 3 subordinates per pen were selected using a feed competition test. Digital photos were collected at 10 min intervals for 8 h on days 1, 8, 10 and 12 to record interactions with enrichment. Skin lesions were assessed on days 1 and 12, and salivary cortisol was assessed in weeks 6, 10 and 14 of gestation. More enrichment use was observed in Rotate and Stimulus treatments compared to Constant, and more sows contacted enrichment when straw was provided in the Rotate and Stimulus treatments. There was no difference in the amount of enrichment use by dominants and subordinates, no cortisol concentration elevation in subordinate sows nor any difference in lesion scores. In conclusion, social status had little impact and feeding system is important to reduce stress and aggression.

The effect of different stocking densities on specific growth rate and survival rate of striped snakehead (Channa striata) culture in bucket system

Striped snakehead culture in bucket system with high stock rate at a good living environment, and also adequate feeding can lead to the maximization of production. However, if the stocking density is too high, it can inhibit the survival and growth of fish caused by competition for space, feed and oxygen as well as increased metabolic waste. The purpose of this study was to determine the effect of different stocking densities on the specific growth and survival rate of snakehead fish (Channa striata) in buckets. This study used is Completely Randomized Design consisting of 5 treatments and 4 replications, namely P0 (1 fish/L), P1 (2 fish/L), P2 (3 fish/L), P3 (4 fish/L) and P4 (5 fish/L). The ANOVA results showed that the difference in stocking density had a significant effect (P<0.05) on the growth rate of specific weight and length as well as the survival rate of fish. DMRT showed that P1 was the highest result for specific weight and length growth rates (0.90%/day and 0.80%/day) and the lowest at P4 (0.62%/day and 0.40 %/day). In addition, the highest of survival rate are also shown at P1 (95.42%) and the lowest at P4 (32.75 %).

Intersexual Agonism in Gray Langurs Reflects Male Dominance and Feeding Competition

Male-female agonism varies throughout the primate order with males often dominating females, especially in sexually dimorphic species. While intersexual agonism has been attributed to sexually coercive contexts, it can also occur for other reasons and intersexual dominance may be influenced by the adult sex ratio. If the proportion of males is high, certain males will regularly lose against other males. Loser-effects may then pave the way for some females to dominate these males, an effect that has been described in a few primate species. Here we investigated the frequency, general style, and context of agonism among gray langurs (Semnopithecus spp.). Data were collected at two study sites, at Jodhpur, India (one group), and at Ramnagar, Nepal (two groups). The adult sex ratio varied between 0.077 and 1.000 males to females. At both sites, data on agonistic interactions (aggression and submission) were collected in continuous focal animal and ad libitum sampling techniques during 1,945 contact hours (including 1,220 focal animal hours, total). Although aggression intensity was low, high directional consistency and the rare occurrence of counteraggression suggested a despotic dominance style, a likely prerequisite for dominance effects based on adult sex ratio. Aggression by females against males was very rare and mainly occurred in the defense of offspring. We found little evidence for partial female dominance regardless of adult sex ratio. In a few cases in which a female had a higher dominance index than a male, she did not dominate this male in dyadic encounters. Agonism by males directed at females occurred mainly in a feeding context while male policing and a sexual context were both rare. The latter was mostly restricted to females after they had harassed a sexual interaction or after they had behaved proceptively toward a male. Our study suggests that across species the effect of adult sex ratio on female dominance might be more variable than previously suggested. The fact that most agonism between males and females occurred over food identifies intersexual feeding competition as a new research avenue with potentially important consequences for existing ideas on the costs and benefits of group life and composition.

Group differences in feeding and diet composition of wild western gorillas

The ecological-constraints model posits that living in larger groups is associated to higher travel costs and reduced nutritional intake due to within-group feeding competition setting upper group size limits. While this is critical for frugivorous mammals, the model is less ubiquitous for folivores who feed on more abundant and evenly distributed food. The seasonally frugivorous diet of western gorillas (Gorilla gorilla) provides the opportunity to study the ecological-constraints model in the largest primate species. We investigated how two groups of western gorillas of differing sizes (N = 9, N = 15) in Central African Republic, responded to seasonal variation in fruit availability in terms of activity and diet. We used continuous focal animal sampling during periods of high (July–August 2011) and low (October 2011–January 2012) fruit availability, measured by monthly phenological scores. While diet diversity, resting and moving time did not differ between groups, overall the smaller group spent more time feeding than the larger group although this became less evident when fruit was more available. The smaller group was more frugivorous than the larger group. However, the larger group increased more steeply fruit consumption when fruit was more available, and incorporated more insects, young leaves and bark when fruit was less available, when compared to the smaller group. Up to a certain limit, the flexibility of large, seasonal frugivores to survive on a more folivorous diet may buffer the upper limit group size, suggesting deviation from the ecological-constraints model as in some folivores.

Tight quarters: ranging and feeding competition in a Colobus angolensis ruwenzorii multilevel society occupying a fragmented habitat

Tight quarters: ranging and feeding competition in a Colobus angolensis ruwenzorii multilevel society occupying a fragmented habitat

Constraints on population growth of blue monkeys (Cercopithecus mitis) in Kibale National Park, Uganda

Abstract Changes in population size are driven by environmental and social factors. In spite of repeated efforts to identify the constraints on an unusually low-density population of blue monkeys (Cercopithecus mitis), it remains unclear why this generalist species fails to thrive in Kibale National Park in Uganda. While an unidentified disease may occasionally obstruct conception, it does not seem to limit overall reproductive rates. Infanticide at this site is infrequent due to the long tenures of resident males. Our analyses indicate that the single biggest constraint on blue monkey densities may be feeding competition with grey-cheeked mangabeys (Lophocebus albigena): across Kibale, the densities of these two species are strongly and negatively correlated. Though further analysis is needed to understand the timing and strength of feeding competition between them, we conclude that blue monkeys at Ngogo experience competitive exclusion from grey-cheeked mangabeys, possibly resolving the 50-year mystery surrounding this population.

Intermittent fasting induces chronic changes in the hepatic gene expression of Red Jungle Fowl (Gallus gallus)

BackgroundIntermittent fasting (IF), the implementation of fasting periods of at least 12 consecutive hours on a daily to weekly basis, has received a lot of attention in recent years for imparting the life-prolonging and health-promoting effects of caloric restriction with no or only moderate actual restriction of caloric intake. IF is also widely practiced in the rearing of broiler breeders, the parent stock of meat-type chickens, who require strict feed restriction regimens to prevent the serious health problems associated with their intense appetites. Although intermittent fasting has been extensively used in this context to reduce feed competition and its resulting stress, the potential of IF in chickens as an alternative and complementary model to rodents has received less investigation. In both mammals and birds, the liver is a key component of the metabolic response to IF, responding to variations in energy balance. Here we use a microarray analysis to examine the liver transcriptomics of wild-type Red Jungle Fowl chickens fed either ad libitum, chronically restricted to around 70% of ad libitum daily or intermittently fasted (IF) on a 2:1 (2 days fed, 1 day fasted) schedule without actual caloric restriction. As red junglefowl are ancestral to domestic chicken breeds, these data serve as a baseline to which existing and future transcriptomic results from farmed birds such as broiler breeders can be compared.ResultsWe find large effects of feeding regimen on liver transcriptomics, with most of the affected genes relating to energy metabolism. A cluster analysis shows that IF is associated with large and reciprocal changes in genes related to lipid and carbohydrate metabolism, but also chronic changes in genes related to amino acid metabolism (generally down-regulated) and cell cycle progression (generally up-regulated). The overall transcription pattern appears to be one of promoting high proliferative plasticity in response to fluctuations in available energy substrates. A small number of inflammation-related genes also show chronically changed expression profiles, as does one circadian rhythm gene.ConclusionsThe increase in proliferative potential suggested by the gene expression changes reported here indicates that birds and mammals respond similarly to intermittent fasting practices. Our findings therefore suggest that the health benefits of periodic caloric restriction are ubiquitous and not restricted to mammals alone. Whether a common fundamental mechanism, for example involving leptin, underpins these benefits remains to be elucidated.

A Circularity Evaluation of New Feed Categories in The Netherlands—Squaring the Circle: A Review

The concept of circularity is currently proposed to address key sustainability issues affecting and affected by livestock production. Through a desk study, this paper evaluates some feed sources that are being developed in The Netherlands as an alternative to current feeds, namely food waste; seaweed; and localized production and alternative plant-based feed sources. These feed categories are evaluated according to four circularity criteria. The first two criteria concern standard circularity principles aimed at both stopping and preventing environmental damage as well as a focus on natural resources use efficiency: (1) safeguard the health of ecosystems and (2) avoid the production of unnecessary products and use/recycle biomass effectively, as well as evaluating possible food–feed competition. In addition, two ‘people’ and ‘animal’ centred principles have been integrated: (3) fairness and accessibility and (4) animal health and wellbeing. The article concludes that people and animal centred principles are key to thinking of, developing, implementing, and evaluating circularity initiatives. Moreover, the article suggests that categories such as the local production of soya (approx. 132 ha) or seaweed (approx. 10–15 ha) are as yet irrelevant regarding production volumes within the Dutch context. However, some feed sources such as seaweed, insects, livestock leftovers produced at farms and abattoirs, and food waste might strengthen the transition towards more circular and sustainable practices.

Manure as waste and food as feed: Environmental challenges on Chinese dairy farms

Rapid intensification and decoupling of animal and crop production have contributed to high nutrient losses to the environment from Chinese dairy farms and increasing food–feed competition. This study therefore aimed to understand nutrient management and food–feed competition on Chinese dairy farms. We used bottom-up data from a farm survey amongst 48 dairy farms in Henan, north-central China, between October and December 2020. Herd sizes ranged from 115 to 4289 heads, and 52% of the farms had no cropland or grassland. Farm characteristics were determined to quantify nitrogen and phosphorus flows on dairy farms. Subsequently, nutrient use efficiencies and human-edible protein conversion ratios (HePCR) were calculated and compared amongst farm typologies. We found that Chinese dairy farms largely rely on imported feed and are decoupled from crop production. On-farm croplands play a minor role in feed supply but are overloaded with cattle manure. Average nitrogen and phosphorus use efficiencies at farm level were 20% and 27%, respectively. The HePCR varied from 1.0 to 3.5, with an average of 2.3, indicating that food–feed competition commonly occurs. Farms with higher milk yields and moderate concentrate use performed better in nutrient use efficiencies and HePCR. This inefficient utilisation of nutrients highlights the urgency for developing farm-level guidelines of nutrient management that acknowledge farm differences. Our findings provide insights from both manure- and feed-management perspectives, which could help policy makers to support dairy farms to become more environmentally friendly and contribute to a circular food system.

The Potential of Using Temperate-Tropical Crossbreds and Agricultural by-Products, Associated with Heat Stress Management for Dairy Production in the Tropics: A Review.

Simple SummaryThe two main factors projected to boost milk production are genomic selection and improvement in the quality and digestibility of feedstuff. The focus of the current article is to look at available measures to curb heat stress and enhance the dairy productivity of tropical crossbred cattle, using readily available agricultural by-products in tropical regions. Inherent associations explored by the current work among breed attributes, agricultural by-products, feeding efficiency in the challenging tropical climate, and heat stress management would be invaluable in constructing a predictive and decision support system for farmers.The demand and consumption of dairy products are expected to increase exponentially in developing countries, particularly in tropical regions. However, the intensification of dairy production to meet this increasing demand has its challenges. The challenges ranged from feed costs, resources, and their utilization, as well as the heat stress associated with rearing temperate–tropical crossbred cattle in the tropics. This article focused on key nutritional and environmental factors that should be considered when temperate–tropical crossbred cattle are used in the tropics. The article also describes measures to enhance the utilization of regional feed resources and efforts to overcome the impacts of heat stress. Heat stress is a major challenge in tropical dairy farming, as it leads to poor production, despite the genetic gains made through crossbreeding of high production temperate cattle with hardy tropical animals. The dependence on imported feed and animal-man competition for the same feed resources has escalated feed cost and food security concerns. The utilization of agricultural by-products and production of stable tropical crossbreds will be an asset to tropical countries in the future, more so when scarcity of feed resources and global warming becomes a closer reality. This initiative has far-reaching impacts in the tropics and increasingly warmer areas of traditional dairying regions in the future.

An intergenerational androgenic mechanism of female intrasexual competition in the cooperatively breeding meerkat

Female intrasexual competition can be intense in cooperatively breeding species, with some dominant breeders (matriarchs) limiting reproduction in subordinates via aggression, eviction or infanticide. In males, such tendencies bidirectionally link to testosterone, but in females, there has been little systematic investigation of androgen-mediated behaviour within and across generations. In 22 clans of wild meerkats (Suricata suricatta), we show that matriarchs 1) express peak androgen concentrations during late gestation, 2) when displaying peak feeding competition, dominance behaviour, and evictions, and 3) relative to subordinates, produce offspring that are more aggressive in early development. Late-gestation antiandrogen treatment of matriarchs 4) specifically reduces dominance behaviour, is associated with infrequent evictions, decreases social centrality within the clan, 5) increases aggression in cohabiting subordinate dams, and 6) reduces offspring aggression. These effects implicate androgen-mediated aggression in the operation of female sexual selection, and intergenerational transmission of masculinised phenotypes in the evolution of meerkat cooperative breeding.

The effects of cow dominance on the use of a mechanical brush

An animal’s social position within a group can influence its ability to perform important behaviours like eating and resting, but little is known about how social position affects the ability to express what are arguably less important but still rewarding behaviors, such as grooming. We set out to assess if dominance measured at the feeder is associated with increased use of a mechanical brush. Over a 2-year period, 161 dry cows were enrolled in a dynamically changing group of 20 individuals with access to a mechanical brush. We determined dominance using agonistic behaviors at the feeder and retrospectively analyzed brush use for the 12 most, and 12 least dominant individuals during the week before calving. Cows that were more dominant at the feeder used the brush more, especially during peak feeding times. Agonistic interactions at the brush did not differ between dominants and subordinates and were not related to brushing duration. These findings indicate that social position, calculated using competition for feed, affects mechanical brush access such that subordinates use the brush less than dominant cows independent of competition or time of day.