Relative Feed Intake Research Articles

Residual feed intake and gain alters the performance and carcass traits in Nellore cattle.

The residual intake and gain (RIG) aims to select animals that present low feed intake in relation to the expected. This study aimed to evaluate the associations of selection for RIG with performance and carcass traits in Nellore cattle. Initially, residual feed intake (RFI) and residual gain (RG) were determined. From this, the RIG was calculated, and the animals were classified as efficient and inefficient for RIG. The efficient animals for RIG showed higher daily weight gain (DWG), Longissimus muscle area (LMA), and mid-test metabolic body weight (MMBW) than the inefficient ones. No significant correlations were found between subcutaneous fat thickness (SFT), marbling (MAR), LMA, MMBW, and the RIG. Thus, it's concluded that the RIG is a measure that can be used to identify and select animals with higher rates of DWG and LMA without changes in the dry matter intake (DMI), SFT, and MAR. However, this index should still be observed with caution, as it may be dependent on body size. Based on the findings, the selection of animals according to the RIG can be an important factor to generate phenotypic evolution in characteristics such as weight gain and rib eye area without adverse effects on the carcass fat deposition.

393 The role of on-animal sensors in understanding feed intake, behavior, and performance of grazing livestock

Abstract Intake by grazing animals is difficult to reliably measure in the field, particularly in more diverse grazing systems where pastures vary greatly across time and space in resource availability, which in turn leads to greater variation in animal time budgets and intake patterns. Advances in remote livestock monitoring (e.g., on-animal sensors, walk -over-weighing), and advanced analytics such as machine learning algorithms can contribute to the development of robust, adaptable tools for better understanding of animal performance and behavior in grazing systems. Many existing tools for predicting livestock production require estimates of feed intake, and while estimates based on forage sward characteristics have been developed and used for temperate, relatively homogenous pastures, they are less well defined for more diverse rangelands. These diverse pastures are more difficult to characterize due to their greater variation in quantity and quality; consequently, animal selectivity is greater in more variable pastures. However, such feedback loops between pasture diversity and animal behavior may not yet be adequately represented in biophysical models. On-animal sensors such as accelerometers and GPS devices can be used to develop new ways of assessing relative intake by providing accurate estimates of animal location and behavior profiles, such as the use of machine learning algorithms to detect how much time is spent grazing, walking, ruminating, or resting. Measurements of animal behavior could then be combined with other animal-based methods such as walk-over-weighing and fecal NIR to improve estimates of intake and production for a wide range of extensive grazing environments. Sensor-derived measurements of animal movement could also be used to improve estimates of the energetic costs of grazing, thereby improving estimates of energy available for growth. As an example, data on recent activity and paddock use from on-animal sensors could be entered into a model to estimate current feeding requirements, then combined with weather and pasture quality forecasts. The ensuing baseline could then be used to explore the potential variability of these projections and generate a range for possible expected performance over the next month or season. This approach could be repeated over time, and animal performance and behavior measures used to update model estimates and improve forward projections. These methods could also be used in conjunction with estimates of animal energy requirements to provide real-time prediction of relative feed intake, which would provide a step-change in modelling livestock production in extensive grazing systems. For these approaches to be successful, additional calibration data are needed across a wide variety of environments and species, and the tools must be cost-effective to implement. In summary, on-animal measurements provide an adaptable, data-driven approach that could be integrated with existing tools to improve our understanding of feed intake, behavior, and performance of grazing animals.

190 Implementation of an updated beef energetics and body composition model in the Crop Livestock Enterprise Model (CLEM)

Abstract The Crop Livestock Enterprise Model (CLEM) is a whole-farm bioeconomic model designed to simulate and explore ruminant performance across a wide range of production systems and management strategies. The model features a flexible, component-based structure that allows users to simulate multiple types of livestock production within the same system. Animals in the model are represented on an individual basis, allowing users to explore the effects of between-animal variation on a wide range of performance metrics at the animal and farm system levels. Recently, two new features were introduced to improve ability of CLEM to represent ruminant production systems: a user-defined timestep, and a new energetics model (based on the Australian ruminant feeding standards) that adds the ability to model changes in body composition in addition to existing predictions of body weight gain and feed intake. The change in timestep from monthly to daily was required to implement the new energetics model and allows for greater ability to compare CLEM results against field data, but other timesteps (e.g., weekly) can also be used depending on user preference. The Australian ruminant feeding standards were integrated with the existing CLEM modelling framework to create a revised energetics model for CLEM capable of predicting body composition, with additional updates to prediction of relative feed intake and the effect of diet type on feed quality. The energetics model was then evaluated for prediction of feed intake (DMI), final empty body weight (EBW), and fat and protein gain (Table 1) in feedlot cattle. The evaluation dataset consisted of treatment means (n = 29) from studies of Angus or British cross steers whose body composition (fat and protein) had been measured by serial slaughter. The updated model performed well for predicting final EBW, underpredicting by 2.35 kg on average (0.55% of the observed mean). Dry matter intake was underpredicted for 80% of treatments, with mean bias averaging 1.7 kg/d across all treatments and a root mean square prediction error (RMSPE, % of the observed mean) of 25%. Data on fat and protein gain was more variable than for EBW, and the model overpredicted protein gain and underpredicted fat gain in general, with mean bias of -51 g/d (RMSPE 42%) for protein and 270 g/d (RMSPE 58%) for fat. The addition of a daily timestep and a revised energetics model add to utility of CLEM by allowing for more in-depth exploration of the effects of feeding and management over time on intake, body weight gain, and body composition. The current version of CLEM can be downloaded from the APSIM Initiative website; and an upcoming update with additional options for prediction of intake and performance for both feedlot and grazing cattle will be made available.

Multifunctional role of dietary copper to regulate stress-responsive gene for mitigation of multiple stresses in Pangasianodon hypophthalmus

It is an urgent needs to address climate change and pollution in aquatic systems using suitable mitigation measures to avoid the aquatic animals' extinction. The vulnerability and extinction of the aquatic animals in the current scenario must be addressed to enhance safe fish food production. Taking into consideration of such issues in fisheries and aquaculture, an experiment was designed to mitigate high temperature (T) and low pH stress, as well as arsenic (As) pollution in fish using copper (Cu) containing diets. In the present investigation, the Cu-containing diets graded with 0, 4, 8, and 12 mg kg-1 were prepared and fed to Pangasianodon hypophthalmus reared under As, low pH, and high-temperature stress. The gene expression was highly affected in terms of the primary, secondary, and tertiary stress response, whereas supplementation of Cu-containing diet mitigates the stress response. Oxidative stress genes such as catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) were significantly upregulated by stressors (As, As + T, and As + pH + T). Whereas, heat shock protein (HSP 70), inducible nitric oxide synthase (iNOS), metallothionine (MT), caspase 3a (Cas 3a), and cytochrome P450 (CYP 450) were highly upregulated by stressors, while dietary Cu at 8 mg kg-1 diet significantly downregulated these gene expressions. Indeed, the immunity-related genes viz. TNFα, Ig, TLR, and immune-related attributes viz. albumin, globulin, total protein, A:G ratio, blood glucose, NBT, and myeloperoxidase (MPO) were also improved with Cu-containing diets. Cu containing diets substantially improved neurotransmitter enzyme (AChE) and vitamin C (Vit C). DNA damage was also reduced with supplementation of Cu at 8 mg kg-1 diet. The growth index viz. final body weight gain (%), specific growth rate, protein efficiency ratio, food conversion ratio, relative feed intake, and daily growth index were noticeably enhanced by Cu diets (4 and 8 mg kg-1 diet). The growth-related genes expressions viz. growth hormone (GH), growth hormone regulator 1 (Ghr1), growth hormone regulator β (Ghrβ,) myostatin (MYST), and somatostatin (SMT) supported the growth enhancement with Cu at 8 mg kg-1 diet. The bioaccumulation of As was reduced with Cu-containing diets. The fish were infected with Aeromonas hydrophila at the end of the 105 days experimental trial. Cu at 8 mg kg-1 diet improved immunity, reduced the cumulative mortality, and enhanced the relative percentage survival of the fish. The results revealed that the innovative Cu diets could reduce the extinction of the fish against climate change and pollution era and produce the safest production that is safe to humans for consumption.

Dietary manganese nano-particles improves gene regulation and biochemical attributes for mitigation of lead and ammonia toxicity in fish

In the present study, we explored the capability of manganese nanoparticles (Mn-NPs) to alleviate the toxicity induced by lead (Pb) and ammonia (NH3) toxicity in Oreochromis niloticus (GIFT strain). The experiment followed a completely randomized design, including a control group (Mn-NPs-0 mg kg−1 diet) and groups exposed to Pb and NH3 alongwith Mn-NPs at 2 and 3 mg kg−1. Cortisol levels were significantly elevated in Pb + NH3 group whereas reduced by Mn-NPs diets. Gene expressions of HSP 70, iNOS, CYP 450, and Cas 3a were notably upregulated by Pb + NH3 group and downregulated by Mn-NPs diets. The cellular metabolic enzymes were affected by Pb + NH3 exposure and mitigated by Mn-NPs diets. The liver and kidney exhibited reduced activities of catalase, superoxide dismutase, and glutathione-s-transferase with Mn-NPs diets. Concurrently, immune-related genes such as total immunoglobulin (Ig) and tumor necrosis factor (TNFα) were upregulated in the Mn-NPs-fed groups. Growth performance indicators, including weight gain %, feed conversion ratio, specific growth rate, protein efficiency ratio, and relative feed intake were adversely affected by Pb + NH3 stress but improvement with Mn-NPs diets. Genes associated with growth performance, such as growth hormone (GH), growth hormone regulatory (GHR1), and myostatin, exhibited enhancements in response to Mn-NPs diets. Digestive enzymes, including protease and amylase were also enhanced by Mn-NPs diets. Additionally, Mn-NPs diets led to a reduction in the bioaccumulation of lead. This study aims to investigate the role of Mn-NPs in mitigating the effects of lead and ammonia toxicity on fish by examining various biochemical and gene regulatory factors to enhance fish wellbeing.

Effects of dietary Clostridium butyricum on the growth performance and intestinal health of hybrid groupers (Epinephelus lanceolatus♂ × E. fuscoguttatus♀)

This trial was performed to investigate the effects of Clostridium butyricum on growth and intestinal health of hybrid groupers (Epinephelus lanceolatus♂ × E. fuscoguttatus♀). 300 hybrid groupers were fed five diets containing C. butyricum at 0, 1 × 107, 2 × 107, 3 × 107, 4 × 107 CFU/g for 8 weeks. The results revealed that dietary C. butyricum significantly increased weight gain rate (WGR), specific growth rate (SGR) and relative feed intake (RFI) (P < 0.05). Moderate C. butyricum significantly promoted lipase (LPS), chymotrypsin (CTS), alpha amylase (α-AMS), total antioxidant capacity (T-AOC) activities and up-regulated intestinal manganese superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase (GPx), interleukin10 (IL-10), transforming growth factorβ (TGF-β), zonula occludens protein-2 (ZO-2), zonula occludens protein-3 (ZO-3), Occludin and Claudin-3a mRNA levels, while significantly decreased malondialdehyde (MDA) content and down-regulated intestinal Kelch-like-ECH-associated protein 1 (Keap1) and interleukin 8 (IL-8) mRNA levels (P < 0.05). 1 × 107 CFU/g C. butyricum significantly augmented villus length, muscle thickness and goblet cells in intestine of hybrid groupers (P < 0.05). 1 × 107 CFU/g C. butyricum significantly increased richness and diversity of intestinal microbiota (P < 0.05) and abundance of beneficial bacteria. Meanwhile, 1 × 107 CFU/g C. butyricum decreased the risk of conditional pathogenic bacteria to invade the host.

Effect of feeding plant-based diet to broodstock on the utilization of plant-based diet in the offspring of rainbow trout Oncorhynchus mykiss

This study investigated the effects of nutritional history during the maturation of rainbow trout Oncorhynchus mykiss on the utilization of a plant-based grower diet in the offspring at the juvenile stage. Fishmeal-based (BF) and plant-based (BP) broodstock diets were fed to an F2 line selectively-bred with plant-based diets (Selected) and to the counterpart line (Control) from two months before the start of gonadal development until the end of ovulation (2 × 2 design). Compared to broodstock fed BF, ovulation tended to be delayed in broodstock fed BP, while nutrient composition of the ovulated eggs and egg quality such as hatchability were similar among treatments. From first feeding, offspring were reared on fishmeal-based diets until they reached approximately 6 g body weight (BW). Then, juveniles of each group (Control-BF, Control-BP, Selected-BF, Selected-BP) were fed a plant-based grower diet (GP) to apparent satiation for 8 weeks at 16 °C (3 tanks/treatment). Specific growth rates (% BW/day) of the Selected groups were significantly higher than the Control groups without a significant effect of broodstock diet. Relative feed intake (% BW/day) of the Selected groups and BP groups were significantly higher than the Control groups and BF groups, respectively. Feed efficiency ratios of the Selected groups and BF groups were significantly higher than the Control groups and BP groups, respectively. Whole body manganese and zinc concentrations of the Selected groups were significantly lower than the Control groups. Activities of lipase, trypsin and chymotrypsin in the intestinal digesta, obtained under restricted feeding (2% BW/day), of juveniles from the Selected groups were significantly higher than those from the Control groups, and the activities of lipase and chymotrypsin of juveniles from the BP groups were also significantly higher than those from the BF groups. These results suggest that the nutritional history of rainbow trout broodstock affects the appetite and digestive physiology of the offspring, but minimally affects their growth. Further fortification of nutrients such as microminerals to plant-based grower diets may be necessary to take full advantage of the effect of selective breeding of rainbow trout with plant-based diets, including the effect of feeding them to the broodstock.

Nano-copper Enhances Gene Regulation of Non-specific Immunity and Antioxidative Status of Fish Reared Under Multiple Stresses.

Arsenic pollution, water temperature, and pH are the major concern for aquaculture. Moreover, the aim of the present investigation was to delineate the role of nano-copper (Cu-NPs) in the mitigation of arsenic toxicity, high temperature (34°C) and low pH (6.5) stress on Pangasianodon hypophthalmus. Four isonitrogenous and isocaloric experimental diets of Cu-NPs at 0, 1.0, 1.5 and 2.0mgkg-1 were formulated and prepared. Arsenic pollution, low pH and high temperature stress significantly reduced the anti-oxidative status (super oxide dismutase, catalase, glutathione peroxidase and glutathione-s-transferase), lipid peroxidation, total anti-oxidative capacity and lipid profiling (cholesterol, total lipid, phospholipid, very low-density lipoprotein and triglyceride). Further, the supplementation of Cu-NPs at 1.5 and 1.0mgkg-1 diets noticeably improve the anti-oxidant status and capacity. The stressors groups (As + pH + T, As + T and As) significantly reduced fish immunity viz. albumin, globulin, total protein, albumin globulin ratio (A:G ratio), myeloperoxidase, respiratory burst activities, tumor necrosis factor, total immunoglobulin, and interleukin. Whereas supplementation of Cu-NPs at 1.5 and 1.0mgkg-1 diets improved the immunity of the fish reared under multiple stresses (As + pH + T). Tail DNA %, DNA damage-inducible protein (DDIP) and inducible nitric oxide (iNOS) synthase gene expression were significantly enhanced with exposure to arsenic, low pH and high temperature but supplementation of Cu-NPs protects the tissues against DNA damage and improved the gene expression of iNOS and DDIP. Cu-NPs at 1.5 and 1.0mgkg-1 diets significantly enhanced the body weight gain %, protein efficiency ratio, specific growth rate, daily growth index, relative feed intake and reduced the feed conversion ratio. Whereas, the growth-related gene expression such as myostatin (MYST), somatostatin (SMT) was downregulated by Cu supplementation and upregulated the gene expression of growth hormone regulator 1 and β (GHR1 and GHR β) and growth hormone (GH) gene in fish. Dietary Cu-NPs supplementation protects the fish against bacterial infection and enhances arsenic detoxification in different tissues. The present investigation revealed that supplementation of Cu-NPs at 1.5 and 1.0mgkg-1 diet has the potential to mitigate multiple stress (As + pH + T) in fish.

Dietary lysine requirement of juvenile Pacific white shrimp, Litopenaeus vannamei (Boone, 1931) reared in inland saline water of 10 ppt salinity

A feeding trial of 60 days was conducted to assess the dietary lysine requirement of juvenile Litopenaeus vannamei reared in inland saline water. Seven isonitrogenous (~ 360 g crude protein/kg feed), isolipidic (~ 60 g crude lipid/kg feed) and isocaloric (~ 18 MJ gross energy/kg feed) semi-purified test diets with graded lysine levels viz., 13.7 (L1), 16.3 (L2), 18.7 (L3), 21.4 (L4), 23.8 (L5), 26.3 (L6) and 28.9 g/kg (L7) were formulated and prepared. Three hundred and seventy-eight L. vannamei juveniles (2.75 ± 0.01 g) were randomly distributed (60 no/m3 or 33 no/m2) into seven test groups in triplicates following a completely randomized design. L. vannamei juveniles were fed to the apparent satiation level four times daily. At the end of the feeding trial, the results indicated that dietary lysine levels have significantly (P < 0.05) affected the growth and nutrient utilization parameters in juvenile L. vannamei. An increase (P < 0.05) in final body weight, weight gain percentage (WG%), thermal growth coefficient (TGC), protein efficiency ratio and protein productive value were observed with the increasing dietary lysine levels from 13.7 to 23.8 g/kg after which a decreasing trend was observed. The relative feed intake and feed conversion ratio showed a decreasing trend from lower dietary lysine levels to higher levels. Survival rates of experimented shrimp were not significantly different (P > 0.05) among the treatment groups. The whole body crude protein and crude lipid content of L. vannamei showed significantly (P < 0.05) increasing and decreasing trends, respectively towards the increasing dietary lysine levels. The hepatopancreatic and muscle protein metabolic enzyme activities, haemocyanin and serum total protein content of L. vannamei varied significantly among the treatment groups. The broken-line linear and second-order polynomial regression analysis of WG% and TGC against the dietary lysine levels indicated that the optimal dietary lysine level with confidence interval (CI) for juvenile L. vannamei reared in inland saline water of 10 ppt salinity is 23.46 (22.59–24.88 g/kg, 95% CI) to 25.24 g/kg (24.27–26.53 g/kg, 95% CI) and 23.26 (22.70–24.15 g/kg, 95% CI) to 25.25 g/kg (24.27–26.53 g/kg, 95% CI) of the diet, respectively.

The Effect of Some Food Additives on Growth Parameters of Grass Carp Ctenopharyngodon idella Fingerlings

A laboratory experiment was carried out to investigate the effect of Thepax and Endo Vit. C as feed additives in the formulated diet on the growth performance of grass carp Ctenopharyngodon idella. The feed (30.11% crude protein) manufactured in the laboratory using raw local materials diet. Young grass carp (Average weight 3.36± 0.95 g) obtained from Aquaculture Unit ponds in Al-Hartha Station for Agricultural Researches, North Basrah. The fish were stocked in nine glass aquarium, three replicates for each treatment, of dimensions 60×40×30 cm provided with pumping aeration. The experimental diets included a control T1 (0% additives), T2 (1g Thepax/kg diet) and T3 (1g Endo Vit. C /kg diet) were used in feeding trail of current experiment. The experiment lasted for 57 days (from 29 Nov. to 24 Jan.) and fishes were fed six days a week using 5% of fish weight as feeding ratio. Results of current study reveals that grass carp fed on formulated feed supplemented with Endo vit. C having high growth performance (WG, DGR, RGR and SGR). The lowest Feed conversion ratio (2.511) was recorded in T3 this value was statistically significant (P≤0.05) with T2 while the highest value (2.767) was observed on the control. Protein efficiency ratio, feed intake and gross conversion efficiency were also recorded high values in T3, but control displayed superior values compared with Thepax treatment, which showed higher value of Relative feed intake compared to other two treatments.

The Effect of Corn Starch Substitution with Sargassum sp. Starch in Diet on Grow-Out of Cultivated Rabbitfish, (Siganus guttatus) in Floating Net Cages

Corn starch is a source of carbohydrates for most cultivated fish, includes rabbitfish as one of the herbivores with high economic value. Therefore, rabbitfish requires cheaper carbohydrate sources to have a profitable business in its cultivation. This study was aimed to determine the substitution of corn starch with Sargassum sp. starch in the diet on the growth, relative feed intake, FCR and nutrient retention of rabbitfish. The average weight of rabbitfish used was 51.76±0.12 g/fish. Rabbitfish were cultivated in small net cages (1x1x1.5m) with a stocking density of 20 fish/net cage for 90 days reared. This study used an experimental method with a Completely Randomized Design (CRD). Corn starch (CM) substitution with Sargassum sp. starch (SM) by 0% (A), 21% (B), 42% (C), 63% (D) and 83% (E) used as the treatments with three replicates each. The measured parameters were weight gain (WG), relative growth (RG), relative feed intake (RFI), feed conversion ratio (FCR), protein retention (PR), energy retention (ER), and condition factor (CF). Data were analyzed using the analysis of variance (ANOVA) and Tuckey’s test. The results showed that the lowest FCR in treatment A had no significant effect with treatment B but was significantly different from treatments C, D and E. The WG, RG, RP and CF parameters had the same values at all levels of CM substitution with SM, while RFI and FCR increased with the increasing CM substitution by SM. It also indicated that CM in the rabbitfish diet could be substituted with SM by 83%.

Soğuk, dondurulmuş veya ortam koşullarında depolanan yemlerin gökkuşağı alabalığı (Oncorhynchus mykiss) yavrularında büyüme performansı ve yem tüketimi üzerindeki etkileri hakkında bir ön çalışma

The storage of commercial feeds in a cool and dry place is a prerequisite management strategy to minimize the deterioration of commercial feeds. This study investigated the effects of feed storage conditions on feed intake and growth performances of juvenile rainbow trout (Oncorhynchus mykiss). A total of 240 juvenile rainbow trout, weighing 8.7–10.5 g, were randomly distributed into four groups. Each group was further subdivided into three replicates with 20 fish in each. The experimental fish were fed to apparent satiation twice daily over a 35-days period using four commercial feeds previously kept at different storage conditions, i.e., room temperature storage (20.8°C), cold storage (10°C), or frozen storages (-1.1°C and -15°C). The feed utilization was assessed by relative feed intake (RFI%) and feed conversion rate (FCR), while growth performance was evaluated by the thermal-unit growth coefficient (TGC) and specific growth rate (SGR). The preliminary findings suggest that the food storage conditions did not significantly affect feed intake and growth performance in juvenile rainbow trout. The findings provide practical information for fish farmers in the management of feed storage, which covers a remarkable proportion of the total production costs in aquaculture facilities.

PSIV-B-29 Evaluating the effect of different feeding strategies in feeding behavior through a novel behavior index integrating several components of the feeding behavior of finishing pigs

Abstract Feeding behavior is an area of study that links the nutritional and behavioral sciences. However, describing the feeding behavior of pigs is difficult given the diversity of variables available and the large day-to-day intra-animal variation. The objectives of this study were to create an index integrating information from several components of feeding behavior that accounts for intra-animal variation, and to evaluate the capability of this index to study the impact of different feeding strategies in pigs’ feeding behavior. Feed intake information from 160 pigs during the last 28 days of the finishing phase from 3 datasets was used. For each pig, the sum of the absolute values of the deviation areas between the regression line of the relative cumulative feed intake and the observed cumulative feed intake was used to calculate the weekly index measuring the irregularity of feed intake (IIFI). Spearman’s correlations of IIFI with the number of daily meals (r = -0.42; P &amp;lt; 0.001), meal duration (r = 0.38; P &amp;lt; 0.01), and feed intake per meal (r = 0.41; P &amp;lt; 0.01) indicate that pigs with high IIFI have fewer meals of longer duration and higher feed intake compared to pigs with low IIFI. Analysis of variance in datasets 1 and 2 showed that moving from conventional to feeding precision systems does not interfere with the feeding behavior of finishing pigs (P &amp;gt; 0.05). In dataset 3, pig feeding behavior was more regular in control diets than for pigs fed fibrous diets (IIFI; 164 vs. 197, respectively; P &amp;lt; 0.05). Additionally, IIFI was smaller in pigs fed canola than in pigs fed wheat by-product diets. These results indicate that IIFI integrates information from several components of the feeding behavior of pigs and demonstrates its potential to evaluate the effect of feeding strategies on feeding behavior.

Economic value of residual feed intake in dairy cattle breeding goals

In the Nordic countries of Denmark, Finland, and Sweden, a breeding value for Saved feed is targeted. Saved feed consists of two sub-traits, maintenance and metabolic efficiency, which are evaluated as residual feed intake. This study evaluated residual feed intake in relation to calculated economic values to set breeding goal. Residual feed intake typically is derived using phenotypic or genetic regression. However, when calculating economic value (EV) for residual feed intake, phenotypic and genetic residual feed intake save feed, and so are not relevant; yet, EV is important for the genetic progress of such traits. Thus, phenotypic regression coefficients were used to obtain the economic value of residual feed intake in the current simulation. The SimHerd model was used in this study to quantify the EV of RFI. The economic value of phenotypic residual feed intake ranged from 0.16 to 0.18 €/kg dry matter, corresponding to 0.16 to 0.18 €/Scandinavian feed unit (SFU – 1 SFU corresponds to 0.97 kg dry matter and 6.7 mega joule net energy) in the SimHerd simulation. Thus, the economic value of feed efficiency corresponded to the applied feed price in the simulations (0.18 €/SFU). By splitting phenotypic residual feed intake into two periods (before and after 84 days in milk), we showed that the simulation of biological changes during early lactation showed that the economic value was not dependent on (P > 0.05) residual feed intake being modelled as one or two periods. However, profit per annual cow differed significantly between simulations using one or two residual feed intake periods (P < 0.001). In conclusion, it is very important to select the appropriate the method to estimate breeding values for residual feed intake.

Elucidating the impact of feeding behaviour on body composition in finishing pigs fed ad libitum using an integrative feeding behaviour index

Large variability in body composition is observed in pigs fed and raised in similar conditions. Part of this variation might be explained by the feeding behaviour of pigs, given its effect on metabolic hormones associated with energy regulation and protein metabolism. The objective of this study was to elucidate this relationship by examining body composition with a new index describing feeding behaviour in finishing pigs. Feeding behaviour and body composition information on 138 pigs during the last 28 d of the finishing phase from three trials were used. For each pig, the sum of the areas between the observed relative cumulative feed intake and the regression line for the evolution of relative feed intake over time was used to calculate the new feeding behaviour index. This index quantifies the irregularity of feed intake (IIFI) by integrating different components of feeding behaviour into a single measurement. Body lipids and protein composition were estimated by dual X-ray densitometry at the beginning (day 1) and end of the finishing phase (day 28). The relationship of IIFI with performance and body composition variables was examined using correlation tests and factor analysis within each dataset. In datasets where IIFI was correlated with body composition, linear models were used to quantify the contribution of IIFI to the total variation of body composition. Weak to moderate correlations (r = ±0.31 to ±0.44; P < 0.05) of IIFI with body composition and performance variables were found only in datasets 1 and 2. However, in dataset 2, IIFI was also correlated with daily feed intake (r = - 0.54; P < 0.001). Irregular feeding behaviour is associated to increased proportion of protein (PdDG) and decreased proportion of lipids (LdDG) in body gain. However, IIFI only accounted for 8% to 14% and 10% to 12% of the total variation of PdDG and LdDG in datasets 2 and 1, respectively. Additionally, factor analysis showed that the number of meals and IIFI had high loadings in a factor separate from factors associated with body composition or performance, suggesting that body composition and performance are independent of feeding behaviour. In conclusion, factors other than feeding behaviour might be involved in modulating body composition of finishing pigs fed ad libitum.

The interaction of feeding regime and dietary specification on growth and nutrient utilisation in Yellowtail Kingfish Seriola lalandi

Feeding regimes on fish farms are often disrupted for logistical reasons or adverse environmental conditions. Issues such as these are commonplace with respect to the sea pen culture of Yellowtail Kingfish Seriola lalandi (YTK) in Australia. These disruptions represent periods of feed restriction which lead to reduced productivity. However, production losses may be ameliorated using different feeding strategies or the use of nutrient dense aquafeeds. To examine the potential of these options we conducted an eight-week experiment with sub-adult YTK (stocking weight ~ 0.80 kg) investigating three feeding regimes crossed with two dietary specifications. The feeding regimes were selected following industry consultation; feeding once daily 7 days per week (control), once daily Monday to Friday (economic) or once daily on randomly selected days of the week (random). Regardless of regime all feed was offered to apparent satiation. A standard specification (Std-Spec; 386 g DP kg−1, 15.1 MJ DE kg−1) and high specification diet (High-Spec; 460 g DP kg−1 and 19.2 MJ DE kg−1) were formulated using a similar suite of ingredients. Each of the 6 treatment combinations was fed to three replicate tanks of fish and results were examined using two-way ANOVA. There was a general absence of interaction between the main effects for most production indices. Specific growth rate (SGR) and relative feed intake (RFI) were significantly better in YTK fed 7 days per week than in YTK fed under more restricted regimes, but feeding regime did not affect FCR. The SGR, FCR and condition factor of YTK were significantly better when fed the High-Spec diet than in YTK fed the Std-Spec diet. The RFI of fish fed under restricted regimes was significantly lower than YTK fed 7 days per week, irrespective of diet specification, indicating YTK were not capable of hyperphagia. However, the RFI of YTK fed the Std-Spec diet was significantly higher than YTK fed the High-Spec diet, confirming nutrient or energy density was likely controlling feed intake. Examination of data on digestible protein, fat and energy intake indicated YTK were eating primarily to satisfy their protein requirement and sub-optimal energy intake was indirectly limiting growth. Our results demonstrate YTK have a limited capacity to increase their feed intake as a means of overcoming moderate feed restriction in order to meet nutrient and energy demands. We recommend feeding YTK of this size a high specification diet to apparent satiation once per day 7 days a week in order to maximize their growth, feed efficiency and physical condition.

A novel feeding behavior index integrating several components of the feeding behavior of finishing pigs

Describing the feeding behavior of pigs is difficult given the large day-to-day variations observed for a given animal. The objectives of this study were to create an index that integrates the information from several components of feeding behavior in order to account for intra-animal variation within a day and between days, and to evaluate the capability of this index to study the impact of relevant nutritional factors affecting feeding behavior. Feed intake information from 160 pigs during the last 28 d of the growing phase from three studies was used. For each pig, the sum of the absolute values of the deviation areas between the regression line of the relative cumulative feed intake and the observed cumulative feed intake was used to calculate the weekly index measuring the irregularity of feed intake (IIFI). Spearman’s correlations of IIFI with the number of daily meals (r = −0.42; P < 0.001), meal duration (r = 0.38; P < 0.01), and feed intake per meal (r = 0.41; P < 0.01) indicate that pigs with high IIFI have fewer meals of longer duration and higher feed intake compared to pigs with low IIFI. This shows that IIFI captures information from several components of feeding behavior. Analysis of variance showed no effect of treatment on feeding behavior for datasets 1 and 2. However, the correlation between IIFI and dietary levels of CP (r = 0.34) indicates that diets high in CP were associated with pigs having more irregular meals. In dataset 3, pig feeding behavior was more regular in control diets than in pigs fed fibrous diets (IIFI; 164 vs. 197, respectively; P < 0.05). Additionally, IIFI was smaller in pigs fed canola by-product diets than in pigs fed wheat by-product diets, indicating that the source of fiber may also influence the feeding behavior of pigs. In most cases, IIFI was more effective at identifying differences in feeding behavior between dietary treatments than conventional feeding behavior variables. These results show the ability of IIFI to integrate information from several conventional components of the feeding behavior of pigs and its potential to successfully evaluate the effect of nutritional factors on feeding behavior.

Feed intake, nutrient digestibility and nutrient retention in Atlantic salmon (Salmo salar L.) fed diets with different physical pellet quality

Three feeds with different physical pellet quality but the same formulation were fed to Atlantic salmon for 97 days. Pellet quality was measured as bulk density, durability, fat leakage, hardness, water stability and porosity. The largest difference among the feeds was measured in hardness (201, 236 and 86 Newton for Diet 1, Diet 2 and Diet 3 respectively). The relative feed intake was highest in salmon fed Diet 2 and Diet 3 with no effects of pellet hardness. Growth and feed efficiency ratio were similar among all fish. The apparent digestibility of energy, dry matter, nitrogen and lipid was similar for all feeds, whereas the apparent digestibility of phosphorus and zinc was the lowest in Diet 3. Retention of energy, lipid and nitrogen was also similar for all feeds. Salmon fed Diet 1 and Diet 3 retained more phosphorus than those fed Diet 2. An increased retention of the digested zinc was found in salmon fed Diet 3. This study concludes that physical pellet quality affects feed intake and improve utilisation of feed in salmon if optimised properly. Moreover, pellet hardness can be optimised in commercial scale without compromising feed intake as it has no influence on feed intake.

The Consequence of Aqueous Extract of Tobacco Leaves (Nicotiana tabacum. L) on Feed Intake, Body Mass, and Hematological Indices of Male Wistar Rats fed under Equal Environmental Conditions

Objective While the dangers of consuming tobacco by smoking has been of concern, the hazardous effect of other forms of tobacco consumption (in smokeless form) on health indices are less well explored. In this paper, we explored the effect of different doses of aqueous extract of tobacco leaves on feed intake, body mass, and hematological indices of male Wistar rats under equal environmental conditions. Method Using an oral route of administration, the rats (n = 24; w = 65–85 g; 2–3 weeks old) were administered at different doses of 100, 200, 400, 0 mg/kg body weight (b.w.) per day to group A, B, C, and D for 42 days, after phytochemical and acute toxicity testing of the tobacco leaves. Results Compared to the negative control group (D), packed cell volume, hemoglobin concentration, red blood cells, and lymphocytes reduced dose-dependently in contrast to the white blood cells, neutrophils, mean corpuscular hemoglobin concentration, mean corpuscular hemoglobin, and mean corpuscular volume. As body mass and feed intake in relation to the different doses of aqueous extract of tobacco leaves reduced significantly (p < 0.05), the reverse was observed for body mass and feed intake in relation to room temperature. Conclusions By influencing hematological indices, feed intake, and body mass, the extract of tobacco leaves can be hazardous to health. However, to assess safety and to come up with a conscious conclusion, future studies should explore the effect of the extract on organs histopathology, biochemical parameters, and lipid profile of the body.

Utilization of raw and gelatinized starch by blunt snout bream Megalobrama amblycephala as evidenced by the glycolipid metabolism, glucose tolerance and mitochondrial function

This study aimed to evaluate the influences of dietary raw and gelatinized wheat starch and their ratios on the glycolipid metabolism, glucose tolerance and mitochondrial function of blunt snout bream Megalobrama amblycephala. Three diets incorporating 100% raw starch (R100), 100% gelatinized starch (G100) and 75% raw starch +25% gelatinized starch (R75/G25) were randomly assigned to 15 cages of fish for 10 weeks, after which fish were sampled. Then the remaining fish within each treatment were combined and later split into 6 tanks for a time series sampling in a glucose tolerance test. Daily gain index, relative feed intake and plasma levels of glucose, triglyceride, pyruvate and lactate all showed little difference among all the treatments. The R75/G25 group obtained the highest feed efficiency and tissue (namely liver and the abdominal fat tissue) glycogen contents. However, the highest tissue (namely muscle, liver and the abdominal fat tissue) lipid contents and plasma total cholesterol levels were both observed in the G100 group. In addition, the G100 group obtained significantly higher transcriptions of glucose transporter 2, glucokinase, peroxisome proliferator activated receptor γ and acetyl-CoA carboxylase α, but relatively low transcripts of the genes involved in gluconeogenesis and fatty acid β-oxidation, compared with the R100 group. The R100 group showed the highest glucose clearance rate, while the area under the glucose curve showed no statistical difference. Furthermore, the R100 group had relatively low activities of mitochondrial complex I, II, III and V as well as the transcriptions of cytochrome c oxidase 2, cytochrome b and NADH dehydrogenase 1 and ATP synthase 6 compared with other groups. Overall, our results suggested that high dietary inclusions of gelatinized starch could enhance the glucose transportation, glycolysis, lipogenesis, lipid deposition, glucose tolerance and mitochondrial function of blunt snout bream, while depress the gluconeogenesis and fatty acid oxidation.