Daily Feeding Frequency Research Articles

Daily feeding frequency affects feed intake and body weight management of growing layers

The objective of this study was to investigate the effect of feeding behavior on feed intake and body weight in growing layers and the underlying mechanisms, thereby providing a scientific foundation for optimal feeding practices in growing layers' management. A total of 144 Hy-line brown growing layers of 10 wk old and similar body weight, were divided into 3 treatment groups with different feeding frequency and equal cumulative daily feeding amount: the once-a-day feeding group (F1) was fed at 9:00 am every day, with feeding amount of 150 g/layer; the twice-a-day feeding group (F2) were fed at 9:00 am and 13:00 pm every day, with each feeding amount of 75 g/layer; the 4 times-a-day feeding group (F4) were fed at 9:00 am, 11:00 am, 13:00 pm, and 15:00 pm every day, with each feeding amount of 37.5 g/layer. Pre-experiment lasted for 1 wk and formal experiment lasted for 8 wk. The results indicated that the daily feed intake and body weight were decreased (P < 0.05) while feed conversion ratio was not affected (P > 0.05) as daily feeding times increased. The glandular stomach proportion was significantly increased in twice-a-day feeding group, while liver proportion and ileum length were significantly increased in 4 times-feeding group (P < 0.05). Additionally, 4 times-feeding daily resulted in a significant elevation of blood glucose levels, which may have suppressed feed intake (P < 0.05). In 4 times-feeding group, the plasma triglyceride levels increased as feeding times, accompanied by a notable up-regulation in the mRNA level of appetite-suppressing gene, hypothalamic pro-opiomelanocortin (POMC) and glandular stomach ghrelin. This modulation effectively suppressed the subsequent feed intake and body weight. Therefore, 4 times feeding daily is recommended in growing layers' management, because it reduced the feed cost without affecting the feed conversion efficiency.

Effect of feeding frequency on growth performance, feed transit and digestive enzyme activity of Acipenser dabryanus juveniles

Dabry's sturgeon (Acipenser dabryanus) is critically endangered in China. However, the lack of research on the feeding strategy of this species is detrimental to its conservation management. The present study evaluated the effects of feeding frequency (1, 2, 3, 4 and 5 times per day) on the growth performance, feed transit and digestive enzyme activity of juvenile Dabry's sturgeons (initial weight 0.42 ± 0.09 g) in a continuous flow culture system at a water temperature of 18.2–18.5°C. Single-meal and normal-feeding (1, 2, 3, 4 and 5 times per day) experimental methods were adopted to assess the effect of different feeding frequencies on feed transit. The fish in each treatment of the normal-feeding experiment were fed normally according to the original feeding frequency (1, 2, 3, 4 and 5 times per day). The optimum feeding frequency for juvenile Dabry's sturgeons was determined to be 4 times per day based on the growth performance, feed conversion rate and digestive enzyme activity. The results of the single-meal experiment demonstrated that changes in daily feeding frequency modified residence time in the stomach (S1–S5: 27.2–10.4 h) and intestine (S2–S5: range from 14 to 29.85 h). However, the obtained gastric emptying time varied significantly depending on the experimental approach. The single-meal experiment approach resulted in a longer gastric emptying time of fish fed 1 and 2 times per day (S1: >35 h; S2: 35 h) than those in the normal-feeding experiment (N1: 16 h; N2: 24 h), demonstrating that the single-meal method might change the gastrointestinal emptying strategy of fish. Furthermore, the digestive enzyme activity had daily rhythmic changes and the average digestive enzyme activity was affected by feeding frequency. The average digestive enzyme activity of the fish in N3 or N4 was higher than those of fish in other groups (p < 0.05). In summary, this study provides much useful information for the healthy farming of juvenile Dabry's sturgeons and towards the understanding of digestive physiology, which is of great significance for the protection of Dabry's sturgeon.

Social Network Analysis of Agonistic Behaviour and Its Association with Economically Important Traits in Pigs.

Simple SummaryAggression behaviour has several negative consequences on the performance and welfare of pigs. Here, a Social Network Analysis (SNA) approach was employed to (1) identify individual traits that describe the role of each animal in the aggression; (2) investigate the association of these traits with performance and feeding behaviour traits. The study was conducted on 326 Duroc pigs reared in 29 pens. Several individual centrality traits were identified and used to calculate the Social Rank Index. The Dominant, Subordinate, and Isolated animals represented 21.1%, 57.5% and 21.4%, respectively. No significant correlations were observed between out-degree (number of initiated agonistic behaviours) and growth traits, indicating the similarity of growth patterns for dominant and non-dominant animals. Furthermore, out-degree was correlated positively with average daily occupation time (time at the feeder/day) and average daily feeding frequency (number of visits to the feeder/day), but negatively with average daily feeding rate (gr/min). This may indicate the ability of non-dominant pigs to modify their behaviour to obtain their requirements. The Hamming distances between networks showed that there is no common behaviour pattern between pens. In conclusion, SNA showed potential for extracting behaviour traits that could be used to improve pig performance and welfare.Aggression behaviour has several negative consequences on the performance and welfare of pigs. Here, the Social Network Analysis (SNA) approach was employed to (1) identify individual traits that describe the role of each animal in the aggression; (2) investigate the association of these traits with performance and feeding behaviour traits. The study was conducted on 326 Duroc pigs reared in 29 pens. Several individual centrality traits were identified and used to calculate the Social Rank Index. The Dominant, Subordinate, and Isolated animals represented 21.1%, 57.5% and 21.4%, respectively. No significant correlations were observed between out-degree (number of initiated agonistic behaviours) and growth traits, indicating the similarity of growth patterns for dominant and non-dominant animals. Furthermore, out-degree was correlated positively with average daily occupation time (time at the feeder/day) and average daily feeding frequency (number of visits to the feeder/day) but negatively with average daily feeding rate (gr/min). This may indicate the ability of non-dominant pigs to modify their behaviour to obtain their requirements. The Hamming distances between networks showed that there is no common behaviour pattern between pens. In conclusion, SNA showed the potential for extracting behaviour traits that could be used to improve pig performance and welfare.

Effects of feeding frequency on growth, feed utilization, digestive enzyme activity and body composition of Litopenaeus vannamei in biofloc-based zero-exchange intensive systems

An eight-week feeding experiment was conducted to investigate the effects of daily feeding frequency on the growth, feed utilization, digestive enzyme activity and body composition of Litopenaeus vannamei juvenile reared in biofloc-based zero-exchange intensive culture systems. The experiment was carried out in twelve tanks with 800 L of biofloc-rich water. Juvenile shrimp (1.52 ± 0.37 g) were stocked into tanks at 240 shrimp tank−1 (300 ind m−3). Three feeding frequencies of three, six, twelve times were evenly set in the 24 h of a day for experimental groups of F3, F6, F12 respectively. Each group had four randomly assigned tanks, and the shrimp were cultured for eight weeks with the same daily ration based on the monitoring of feeding trays in F3 group. During the experiment, all the monitored water quality parameters were maintained within acceptable ranges for shrimp culture. At the end of the experiment, the shrimp survival rate was higher than 89.03% in all the three groups. Notably, with the increase of daily feeding frequency from three times to six and further to twelve, significant differences were found as follows: (1) the final weight, growth rate and yield of the shrimp increased; (2) the feed conversion rate decreased while the protein efficiency ratio and protein productive value increased; (3) the specific activities of protease and amylase in the stomach of the shrimp and the specific activity of lipase in the digestive gland increased; (4) the crude protein content of the whole body of the shrimp increased while the moisture content decreased. Taken together, these results demonstrate that daily feeding frequency can affect the growth, feed utilization, digestive enzyme activity and body composition of L. vannamei juvenile reared in biofloc-based zero-exchange intensive systems. Distributing a controlled ration of daily feed at frequent times during 24 h of a day is beneficial for the growth, feed utilization, nutrient digestion, and protein deposition of L. vannamei in biofloc-based systems under controlled conditions.

Indirect genetic effects on the relationships between production and feeding behaviour traits in growing Duroc pigs

Performance and feeding behaviour traits in growing pigs could be affected by social interaction effects when animals are raised in group. So, properly knowing the genetic correlations between direct and social interaction effects among performance and feeding behaviour traits could improve the accuracy of the genetic evaluations. Our aim was to explore the role of feeding behaviour traits (FBT) and indirect genetic effects (IGEs) in the genetic evaluations of growing pigs. Thus, genetic parameters were estimated for production traits (PT): average daily gain, average daily feed consumption, feed conversion ratio and backfat thickness; as well as for FBT: average daily feeding rate, average daily feeding frequency, average daily occupation time and average daily time between consecutive visits. Traits were recorded in 1144 Duroc pigs during the fattening period. Two bivariate models were fitted: classic animal model and an animal model fitting IGE. Estimations were done following Bayesian procedures. Heritability estimates obtained with classic animal model for all studied traits were medium-high. The additional heritable variation captured by IGE supposed that the ratios of total genetic variance to phenotypic variance (T2) were higher than the heritability estimates obtained with the classic model, except for occupation time trait, when a lower value (0.20 ± 0.19) was estimated. This is due to a high and negative correlation between IGE and direct genetic effects (DGEs) of this particular trait (−0.78 ± 0.27). Results from classic animal model do not evidence a clear role of FBT to improve the accuracy of breeding value predictions for PT; only average daily feeding rate seems to show a positive correlation (around 0.50 to 0.60) with average daily gain, average daily feed consumption and backfat thickness. However, when IGE model was fitted, the number of estimates of genetic correlations between FBT and PT showing a relevant magnitude increased, generally for the correlations between IGE of FBT and DGE of PT; or particularly for the correlations between IGE of average daily feeding frequency, and the IGE of all the PT, except average daily gain. Thus, in evaluations using the animal model with IGE fitted, the inclusion of FBT could aid the improvement of the accuracy of breeding value predictions for PT. This is a consequence of the improved genetic relationships between traits that can be fitted when considering such models.

Effect of feeding time and frequency on gut transit and feed digestibility in two fish species with different feeding behaviours, gilthead seabream and Senegalese sole

A comparative approach was adopted to assess the effect of different feeding strategies on feed transit and daily oscillations of apparent digestibility coefficients (ADCs) of dry matter, protein, and energy, in two species with different feeding habits, gilthead seabream and Senegalese sole. For this purpose, fish juveniles were consecutively fed with a standard and a marked diet (yttrium oxide) and were sampled at difference post-prandial times. Mathematical models were constructed to predict filling and evacuation of the stomach and intestine in gilthead seabream, and the whole digestive tract in Senegalese sole. Results demonstrated that changes in daily feeding time and frequency, modified the feed transit rate and residence time in the gut as well as the apparent digestibility, with obvious consequences for the utilization of nutrients. Variations in apparent digestibility were also observed along the daily cycle. Besides, the obtained response varied significantly depending on the studied fish species, due to the interspecific differences in the anatomy, digestive physiology, and feeding habits. Allocating the whole daily meal in one ration resulted in fast gut filling rate and low apparent digestibility in both species. In gilthead seabream, feeding protocol did not influence the stomach and intestine evacuation rates. However, in Senegalese sole, frequent meals during the whole daily cycle resulted in a faster gut evacuation. Very frequent diurnal feeding led to highest ADCs in both species; although, such higher digestibility values were not necessarily related to longer feed residence times within the gut in gilthead seabream. The results obtained from this study can be useful to establish optimized feeding protocols that help to reduce the production costs and undigested debris in the effluents.

Optimization of feeding quantity and frequency to rear the cyprinid fish Garra rufa (Heckel, 1843)

Garra rufa has a high commercial value, but their rearing methods are still unknown. Aspects like an adequate daily dose and feeding frequency need to be investigated. This work aimed to establish the optimal feed dose per day to obtain satiation and the optimal frequency of feeding to rear a specific size class of G. rufa. A total of 60 fish were distributed by six aquaria containing 10 fish. First, the fish were fed twice per day, by providing a feed dose correspondent to 1% of their body weight and increasing 0.1 g/fish on the following days, until finding feed leftovers on the next morning. Afterwards, the fish went through a 1 month experimental trial to evaluate the optimal feeding frequency. Fish growth was compared between feeding the optimal daily dose distributed in two or three feeding moments per day. The optimal dose that ensured satiation was 0.042 g fish−1 day−1 (3.2% of fish’ body weight). Feeding the fish three times per day promoted higher growth rates, since the fish’ total length was statistically different between feeding frequencies. Statistically significant differences between feeding frequencies were not observed for growth performance parameters. These results contribute to the aquaculture of this target species, allowing fish industry to more efficiently respond to the high demand for G. rufa and, simultaneously, for its preservation in the wild.

Growth, Gastrointestinal Tolerance and Stool Characteristics of Healthy Term Infants Fed an Infant Formula Containing Hydrolyzed Whey Protein (63%) and Intact Casein (37%): A Randomized Clinical Trial.

To investigate whether healthy term infants, fed an infant formula containing hydrolyzed whey protein (HWP-F, hydrolyzed whey/intact casein =63/37), differ in growth, gastrointestinal tolerance and stool characteristics from those fed an infant formula containing intact whey protein (IWP-F, intact whey/intact casein =61/39) or breast milk. Healthy term infants, born within 14 days of the study’s commencement, were randomly assigned to be fed IWP-F or HWP-F until 13 weeks of age, and breast-fed (BF) infants were enrolled as a reference group. Anthropometric measurements, gastrointestinal tolerance indexes and stool characteristics were assessed at baseline, and 7 and 13 weeks of age. There were no significant differences in any growth measurements and the occurrence of crying, spit-up and difficult defecation among the three feeding groups during the study period. However, daily feeding frequency was consistently lower in the formula-fed infants than in the BF group throughout the study (p < 0.05), and infants in the HWP-F group consumed more formula than those in the IWP-F group at 7 and 13 weeks of age (p ≤ 0.002). The HWP-F-fed infants had more similar stool characteristics to the breast-fed infants than infants in the IWP-F group at 13 weeks of age, regardless of frequency, volume, color or consistency of stool. This study demonstrates that the HWP-F could support the normal growth of healthy term infants, to a comparable extent to that of breast-fed infants during the first three months of life. Moreover, stool characteristics of HWP-F-fed infants are much closer to breast-fed infants than IWP-F-fed infants, but no significant gastrointestinal tolerance improvement was observed in HWP-F group.

The effect of feeding frequency, water temperature, and stocking density on the growth of river puffer Takifugu obscurus reared in a zero-exchange water system

The effects of daily feeding frequency (Exp I), water temperature (Exp II), and stocking density (Exp III) on the growth of river puffer, Takifugu obscurus, juvenile fish of 10 and 40 g in body weight were examined to develop effective techniques to produce river puffer in a non-exchange water system. In Exp I, fish were fed commercial floating feed with 45 % protein one to five times per day to apparent satiation each by hand daily for 8 weeks at 25 °C. In both the 10- and 40-g size groups, the final body weight, daily feed consumption, and weight gain of fish fed one meal per day were significantly lower than those of fish fed five meals per day (P < 0.05). However, there were no significant differences in the final body weight, daily feed consumption, and weight gain among fish fed two, three, and five meals per day. Feed efficiency showed decreasing tendency with increasing size of fish. In Exp II, fish of 10 and 40 g in initial body weight were reared with the commercial feed at 15–30 °C for 8 weeks. The weight gain of fish increased with raising water temperature up to 25 °C and decreased drastically at 30 °C for both sizes. The Q10 of specific growth rate was decreased with raising water temperature from 5.04 (temperature interval, 15–20 °C) to 0.66 (25–30 °C) for the 10-g fish and from 4.98 to 0.31 for the 40-g fish. In Exp III, the effect of stocking density on growth was examined with fish of 10 and 40 g in initial body weight. The final body weight for initial stocking densities of 4, 8, and 12 kg/m3 was significantly higher than that of 20 kg/m3 for the 10-g fish, and the final stocking density reached 10.1, 19.2, 28.7, and 39.9 kg/m3, respectively. For the 40-g fish, the final body weight for initial stocking densities of 3 and 6 kg/m3 was significantly higher than that of 9 and 15 kg/m3 and the final stocking density reached 7.38, 13.5, 17.1, and 27.5 kg/m3, respectively (P < 0.05). In both groups, weight gain tended to decrease with increasing stocking density; however, survival showed no significant difference.

Feeding behaviors of three tropical scleractinian corals in captivity

This study examined the capture rates and prey digestion of three corals species in two genera (Acropora and Pocillopora) found dominantly in Thailand and the Federated States of Micronesia using Artemia salina nauplii as a food source. In addition, feeding during day and night times of corals was investigated. Results showed that all three coral species, namely, Acropora millepora, Acropora nobilis, and Pocillopora damicornis captured and consumed A. salina nauplii under both light and dark conditions. The capture rates of the three species ranged between 0.44 and 2.39 individuals/polyp/12 h. The results also showed complete digestions of A. salina nauplii by A. millepora and A. nobilis after 2 h, whereas P. damicornis took 2.5 h to complete the prey digestion. Even though feeding corals with Artemia is not a novel implication since this is widely used, the results of optimum daily feeding frequency of corals by Artemia may be applied for optimum corals growth and survival in captivity or aquarium.

Estimation of the ideal dosage and feeding frequency for Garra rufa (Cyprinidae)

Event Abstract Back to Event Estimation of the ideal dosage and feeding frequency for Garra rufa (Cyprinidae) Mafalda M. R. S. Catarino1, Mónica R. S. Gomes1, Sílvia C. Gonçalves1, 2 and Susana M. F. Ferreira1, 3* 1 MARE – Marine and Environmental Sciences Centre, School of Tourism and Maritime Technology, Polytechnic Institute of Leiria, Portugal 2 MARE – Marine and Environmental Sciences Centre, Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Portugal 3 CFE - Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Portugal Garra rufa are widely used in skin treatments at beauty and wellness institutes. This freshwater species is native from Eurasia and has a large distribution area, including river basins in Turkey and Iran. It has a high commercial value and arouse interest among fish farmers. Even so, G. rufa methods of production are still unknown. In fact, aspects that sustain a rapid and healthy growth of these fish need to be investigated, like an adequate daily dose and feeding frequency. This work aimed to establish: 1) the optimal feed dose per day, correspondent to the amount necessary for obtaining satiation, with a commercial granulated food; and 2) the optimal frequency of feeding for intensive production of G. rufa in Aquaculture. A total of 60 fishes underwent a 3 weeks acclimation period in laboratory, distributed by 6 aquaria, containing 10 fishes with similar body weight and length. The animals were initially fed with a dose correspondent to 10% of their body weight. This dose was gradually increased until complete satiation of the fishes. An optimal dose of 0.04 g fish-1 day-1 was found. Afterwards, the same fishes went through a 1 month experimental trial to evaluate the ideal feeding frequency. Fish growth was compared between feeding 0.2 g twice per day and 0.1333 g three times per day. Variations in size (total and fork length), plus body weight were evaluated at the end of the trial. One-Way ANOVA procedures revealed that the variations in weight and in fork length were similar between treatments, but the variation in total length was significantly higher with 3 daily feeding moments (p<0.05). In conclusion, the present results showed that the optimal dose that ensures satiation for G. rufa is 0.04 g fish-1 day-1 and that 3 daily feeding moments promotes higher growth rates. Acknowledgements This work was developed in the scope of the project “SpaGaRufa – Production of the fish Garra rufa for therapeutic purposes”, an Ignition Fund INOV C, co-financed by the Operational Programme of the Centre Region (+ CENTRO), National Strategic Reference Framework (QREN 2007-2013) and the European Fund for Regional Development, developed by GIRM-IPL – Group of Investigation in Marine Resources from the Polytechnic Institute of Leiria. Keywords: Aquaculture, Diet, Doctor fish, Growth, ad libitum Conference: XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015. Presentation Type: Poster Presentation Topic: Physiology, Behavior and Toxicology Citation: Catarino M, Gomes M, Gonçalves S and Ferreira S (2015). Estimation of the ideal dosage and feeding frequency for Garra rufa (Cyprinidae). Front. Mar. Sci. Conference Abstract: XV European Congress of Ichthyology. doi: 10.3389/conf.fmars.2015.03.00076 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 11 Nov 2015; Published Online: 17 Nov 2015. * Correspondence: Prof. Susana M. F. Ferreira, MARE – Marine and Environmental Sciences Centre, School of Tourism and Maritime Technology, Polytechnic Institute of Leiria, Peniche, 2520-641, Portugal, susana.ferreira@ipleiria.pt Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Mafalda M. R. S. Catarino Mónica R. S. Gomes Sílvia C. Gonçalves Susana M. F. Ferreira Google Mafalda M. R. S. Catarino Mónica R. S. Gomes Sílvia C. Gonçalves Susana M. F. Ferreira Google Scholar Mafalda M. R. S. Catarino Mónica R. S. Gomes Sílvia C. Gonçalves Susana M. F. Ferreira PubMed Mafalda M. R. S. Catarino Mónica R. S. Gomes Sílvia C. Gonçalves Susana M. F. Ferreira Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

조피볼락(Sebastes schlegeli) 치어의 배합사료 적정 공급률과 공급횟수

Two feeding trials were conducted to investigate the effects of feeding rate and frequency on growth performance and body composition of juvenile Korean rockfish Sebastes schlegeli reared at <TEX>$15.0{\pm}0.3^{\circ}C$</TEX>. In the first trial, three replicate fish groups averaging <TEX>$2.07{\pm}0.03g$</TEX> were fed a commercial diet with one of seven different daily feeding rates: 1.00%, 2.00%, 2.50%, 2.75%, 3.00%, 3.25%, and satiation (3.34%) based on body weight (BW). After four weeks of feeding, fish fed the 3% diet showed significantly higher weight gain (WG) and feed efficiency (FE) than fish that received the other feeding rates. In the second trial, the optimum feeding frequency was evaluated with three replicate fish groups averaging <TEX>$2.04{\pm}0.03g$</TEX>. Fish were fed a commercial diet at 2.87% BW with six different daily feeding frequencies: 2, 3, 4, 5, 7, or 9 meals. After four weeks of feeding, WG, specific growth rate, FE, and protein efficiency rate in fish fed 3 meals <TEX>$d^{-1}$</TEX> were significantly higher than those of fish fed 7 or 9 meals <TEX>$d^{-1}$</TEX>. In both feeding trials, proximate composition of the entire body changed depending on the feeding rate or frequency. A broken-line regression analysis based on weight gain suggested that the optimum daily feeding rate and frequency for juvenile Korean rockfish at <TEX>$15^{\circ}C$</TEX> was 2.9% BW <TEX>$d^{-1}$</TEX> and 2-3 meals <TEX>$d^{-1}$</TEX>, respectively.

Evaluation of Agar-Bound Microparticulate Diet as Alternative Food in Abalone Hatchery: Effects of Agar Concentrations and Feeding Frequencies

The performance of an agar-bound microparticulate diet (A-MPD) was evaluated on feeding postlarval abalone Haliotis asinina, focusing on the effects of agar concentrations and feeding frequencies. Larval abalone, obtained from the Southeast Asian Fisheries Development Center, Aquaculture Department hatchery, were reared in 60-L flow-through tanks with UV-filtered seawater. They were fed 1,200 mg A-MPD bound with either 5.0 mg/mL agar solution, 7.5 mg/mL agar solution, 10.0 mg/mL agar solution, and 12.5 mg/mL agar solution, or a natural diet consisting of diatoms at different feeding frequencies (daily, every other day, or every 2 d) starting at day 5. A 5 × 3 factorial experiment in a completely randomized design tested the effects of various treatments on postlarval settlement and survival after days 15 and 90. Scheffé's postcomparison test determined differences among treatments means. Postlarval settlement and survival were not significantly different in diets bound with higher agar concentrations and tested in 3 feeding frequencies. At lower levels of agar incorporation in diets, however, settlement and survival counts became significantly higher on daily feeding. Postlarval settlement and survival were significantly highest with abalone fed a diet bound with 7.5 mg/mL agar solution on a daily feeding frequency. Average percent weight loss in the feed was higher with lower levels of agar incorporation. Average particle size of both A-MPD and diatoms was 4–5 µm. Crude protein content of A-MPD was 42.7%; that of diatoms was 14.9%. A-MPD may be used as alternative food in abalone hatcheries with the incorporation of 7.5 mg/mL agar solution fed daily to abalone.

Acidic Digestion in a Teleost: Postprandial and Circadian Pattern of Gastric pH, Pepsin Activity, and Pepsinogen and Proton Pump mRNAs Expression

Two different modes for regulation of stomach acid secretion have been described in vertebrates. Some species exhibit a continuous acid secretion maintaining a low gastric pH during fasting. Others, as some teleosts, maintain a neutral gastric pH during fasting while the hydrochloric acid is released only after the ingestion of a meal. Those different patterns seem to be closely related to specific feeding habits. However, our recent observations suggest that this acidification pattern could be modified by changes in daily feeding frequency and time schedule. The aim of this study was to advance in understanding the regulation mechanisms of stomach digestion and pattern of acid secretion in teleost fish. We have examined the postprandial pattern of gastric pH, pepsin activity, and mRNA expression for pepsinogen and proton pump in white seabream juveniles maintained under a light/dark 12/12 hours cycle and receiving only one morning meal. The pepsin activity was analyzed according to the standard protocol buffering at pH 2 and using the actual pH measured in the stomach. The results show how the enzyme precursor is permanently available while the hydrochloric acid, which activates the zymogen fraction, is secreted just after the ingestion of food. Results also reveal that analytical protocol at pH 2 notably overestimates true pepsin activity in fish stomach. The expression of the mRNA encoding pepsinogen and proton pump exhibited almost parallel patterns, with notable increases during the darkness period and sharp decreases just before the morning meal. These results indicate that white seabream uses the resting hours for recovering the mRNA stock that will be quickly used during the feeding process. Our data clearly shows that both daily illumination pattern and feeding time are involved at different level in the regulation of the secretion of digestive juices.

Effect of feeding frequencies on growth performance of Clarias gariepinus

Investigations were carried out on the growth performance of juvenile Clarias gariepinus using four different feeding frequencies. Two hundred and forty juveniles (8.6 +0.0 g) were stocked in eight aquaria tanks (120 x 60 x 80 cm) to a capacity of 120 litres and fed 1,2,3 and 4 times a day respectively for 70 days. Final body weight, relative growth rate (RGR) and specific growth rate (SGR) were measured significantly lower at F1 (1 time/day) and F2 (2 times/day) than F3 (3 times/day) and F4 (4 times/day) treatment (p F4>F1>F2. There were no significant differences for survival rates (p>0.05) within the treatments. The results showed that weight gain and growth performance of Clarias gariepinus juvenile increased with increased feeding frequency. The relative growth rate (RGR) of the experimental fish ranged from 972% (in twice daily feeding frequency) to 1,801% (in thrice daily feeding frequency) and the highest was in three times daily feeding frequency while the twice daily feeding frequency had the least. Specific growth rate was lowest in once daily feeding frequency 3.56% and highest value of 4.21% was recorded in thrice daily feeding frequency. Keywords: specific growth rate, relative growth rate, Clarias gariepinus.

Effect of Feeding Frequency, Water Temperature, and Stocking Density on the Growth of Tiger Puffer, Takifugu rubripes

Abstract Effects of daily feeding frequency, water temperature, and stocking density on the growth of tiger puffer, Takifugu rubripes, fry were examined to develop effective techniques to produce tiger puffer in a closed recirculation system. Fish of 4, 14, and 180 g in initial body weight were fed commercial pellet diets once to five times a day to apparent satiation each by hand for 8 or 12 wk at 20 C. Daily feeding frequency did not affect the growth of 14‐ and 180‐g‐size fish. However, the daily feed consumption and weight gain of the 4‐g‐size fish fed three and five times daily were significantly higher than those of fish fed once daily (P &lt; 0.05). Fish of 4 and 50 g in initial body weight were reared with the pellet diet at 15–30 C for 8 wk. The weight gain of fish increased with increasing water temperature up to 25 C and decreased drastically at 30 C for both sizes. Similar trends were observed for feed efficiency, although 4‐g fish had highest efficiency at 20 C. Effects of stocking density on growth were examined with fish of 8, 13, and 100 g in initial body weight. Fish were reared with the pellet diet for 8 or 16 wk at 20 C. Fish were placed in floating net cages in the culture tank, and the stocking density was determined based on the total weight of fish and volume of the net cage. Fish of 8 g in body weight grew up to 35–36 g during the 8‐wk rearing period independent of the stocking density of 8, 15, and 31 kg/m3 at the end of rearing. Final biomass per cage reached 32, 60, and 115 kg/m3 for 13‐g‐size fish, and 10, 18, and 35 kg/m3 for 100‐g‐size fish, and the growth of the fish tended to decrease with increasing stocking density for both sizes.

Effects of Daily Feeding Time and Frequency on Channel Catfish, Ictalurus punctatus Production in Earthen Ponds

A pond study was conducted to evaluate effects of daily feeding time and frequency on channel catfish, Ictalurus punctatusproduction, feed efficiency, processing yield, and body composition. Channel catfish fingerlings (initial weight = 22 g/fish) were stocked into eighteen, 0.4-ha ponds at a rate of 24,700 fish/ha. The fish were fed to apparent satiation with a commercial 28% protein diet once daily in the morning or afternoon, or twice daily in both morning and afternoon for two growing seasons. On average, fish on the twice-a-day feeding regime were fed about 2,000 kg/ha more diet than fish fed once daily, but due to the large variation in diet input among ponds there were no significant differences in the amount of diet fed among treatments. No differences were observed in weight gain per fish, estimated survival, net production, visceral fat, or fillet proximate composition among treatments. Feed conversion ratio decreased in fish fed once daily in the morning compared to fish fed once daily in the afternoon or twice daily. Fish fed twice daily had higher carcass and fillet yields than fish fed once daily in the afternoon. However, whether the differences in feed conversion ratio and processing yield are true biological responses needs further investigation. Results from this study indicate that there are few, if any, advantages in feeding food-sized channel catfish twice daily or at a certain time of day. Therefore, we recommend that food-fish in grow-out ponds be fed once daily to apparent satiation but not exceeding what an individual pond can “metabolize,” and feeding should begin early in the morning as soon as dissolved oxygen levels begin to increase.

Plant secondary metabolites alter the feeding patterns of a mammalian herbivore (Neotoma lepida)

Mammalian herbivores are predicted to regulate concentrations of ingested plant secondary metabolites (PSMs) in the blood by modifying the size and frequency of feeding bouts. It is theorized that meal size is limited by a maximum tolerable concentration of PSMs in the blood, such that meal size is predicted to decrease as PSM concentration increases. We investigated the relationship between PSM concentration in the diet and feeding patterns in the herbivorous desert woodrat (Neotoma lepida) fed diets containing phenolic resin extracted from creosote bush (Larrea tridentata). Total daily intake, meal size and feeding frequency were quantified by observing the foraging behavior of woodrats on diets containing increasing concentrations of creosote resin. Desert woodrats reduced meal size as resin concentration in the diet increased, resulting in an overall reduction in daily intake and regulation of resin intake. Moreover, desert woodrats were able to detect resin concentrations in the diet and regulate the intake of resin very rapidly. We suggest that the immediate and sustained ability to detect and regulate the intake of resin concentrations during each foraging bout provides a behavioral mechanism to regulate blood concentrations of resin and allows desert woodrats to make "wise" foraging decisions.

Diet effect on the daily feeding behaviour, frequency and characteristics of meals in dairy goats

An experiment of 4×3 weeks was carried out to analyse intake level and rate, number of meals and chewing activities of dairy goats. Four pairs of Alpine and Saanen goats in mid lactation were fed ad libitum four complete diets CR, CS, FR and FS in a Latin square design. Forage/concentrate ratio in these diets was low (C=30/70) or high (F=55/45) and starch, rapidly (R) or slowly (S) degradable in the rumen (barley and maize, respectively). The goats were housed in stalls and fitted with jaw movement recorders. Intake levels were also recorded over 4×48 h. Diets were distributed twice daily. Total daily intake was significantly higher ( P<0.01) on R diets (+200 g DM/day). Intake rates during main meals were 12.6, 12.2, 9.1 and 8.7 g/min, respectively, on CR, CS, FR and FS ( P<0.05). The number of secondary meals decreased with the increase of forage content. Intake during secondary meals was 0.84, 0.88, 0.83 and 0.70 kg DM/day, respectively, on CR, CS, FR and FS. Chewing during eating and rumination depended on the type of diet (less than 740 min/day on C and more than 820 min/day on F: P<0.05). In conclusion, goats seem adapt their feeding behaviour to the kind of diet they receive.

Effect of variations in daily feeding frequency and ration size on growth of shrimp, Litopenaeus vannamei (Boone), in zero-water exchange culture tanks

It is generally believed that increasing feeding frequency has immediate benefits, including reduced nutrient leaching and increased shrimp growth. In this study, static-water ecoassays were conducted to determine the effect of feeding frequency and percentage of daily ration on growth of Litopenaeus vannamei and accumulation of inorganic nitrogen and phosphorus in the culture water. Shrimp were fed a semi-purified diet containing 19.5% crude protein. Experiment 1 tested five feeding frequencies (3, 5, 8, 11 and 15 feedings day −1) evenly spaced in time during 24 h. Daily ration was divided in similar amounts for each feeding frequency. Mean shrimp survival was 98.6% for all treatments. No significant differences were found either on shrimp growth or accumulation of total inorganic nitrogen (TIN) or total reactive phosphorus (TRP) regardless of feeding frequency. In experiment 2 daily rations were offered manually 1 (100% at 0800 h), 2 (50% each at 0800 and 2000 h), 3 (33% each at 0800, 1400 and 2000 h), 3 + (45, 20 and 35% at 0800, 1400 and 2000 h, respectively), 4 (25% each at 0800, 1200, 1600 and 2000 h), 4 + (40, 15, 15 and 30% at 0800, 1200, 1600 and 2000 h, respectively) and 6 (16.6% each at 0800, 1030, 1300, 1600, 1800 and 2000 h) times day −1; and with automatic feeders 15 times day −1 (every 96 min). Shrimp survival was 100% for all treatments. Although mean shrimp growth was highest at 2 feedings day −1 no significant differences were found among feeding treatments. Accumulation of TIN in the culture water was significantly lower for tanks receiving feed 2 times day −1 compared to 1 and 3 times day −1. Levels of TIN were not significantly different among the other feeding treatments. Accumulation of TRP was not significantly different regardless of feeding treatment. These data indicated that under these culture conditions increasing feeding frequency or manipulating ration size did not significantly improve shrimp survival or growth. The only significant environmental effect detected in the culture water was a reduction of TIN at a feeding frequency of 2 compared to 1 and 3 times day −1 in experiment 2. The authors suggest that multiple feedings may not be advantageous for some static culture systems, and that the cost-effectiveness of multiple feedings be evaluated for different feeds and culture systems.