Meta-Analysis of Bacillus in Laying Hen Nutrition: Feed Intake, Feed Conversion Ratio and Egg Productive Indices

The aim of this study was to evaluate the effect of algal oil with very high level of docosahexaenoic acid (DHA, C22:6n-3) used as fat source in the diet for laying hens, on egg yolk lipids fatty acid composition, as well as egg production and egg quality indices, in comparison with other dietary fat sources. The experiment was carried out on 168 ISA Brown hens (25 to 60 wks of age), allocated to 7 groups of 12 replicates (cages), with two birds in each cage. The experimental diets were supplemented with 2% of different fat sources, i.e. soybean oil (SO), coconut oil (CO), rapeseed oil (RO), linseed oil (LO), camelina oil (CAO), fish oil (FO), or algal oil (AO). Laying performance indices, i.e. egg production, mean egg weight, feed intake, feed conversion ratio, or egg and eggshell quality parameters were not affected by used fat sources (P>0.05). Dietary fat sources significantly influenced on egg yolk lipids fatty acids composition. Thus, AO addition caused some changes in the yolk lipid profile that were favorable from the dietary perspective, i.e., increased concentration of eicosapentaenoic acid (EPA) and DHA (P<0.05). However, boiled eggs from hens fed a diet with AO were characterized by an inferior flavour and taste to those from other groups. In conclusion, the results of this experiment, have shown that the use of AO in the laying hens nutrition is an efficient way to increase the deposition of n-3 long chain polyunsaturated fatty acids (n-3 LCPUFAs) in eggs, without negative effect on egg performance, however further researches, aiming to establish optimal AO dietary level that does not adversely affect the organoleptic properties of eggs, are needed.

Simple SummarySensors, routinely collected on-farm tests, and other repeatable, high-throughput measurements can provide novel phenotype information on a frequent basis. Information from these sensors and high-throughput measurements could be harnessed to monitor or predict individual dairy cow feed intake. Predictive algorithms would allow for genetic selection of animals that consume less feed while producing the same amount of milk. Improved monitoring of feed intake could reduce the cost of milk production, improve animal health, and reduce the environmental impact of the dairy industry. Moreover, data from these information sources could aid in animal management (e.g., precision feeding and health detection). In order to implement tools, the relationship of measurements with feed intake needs to be established and prediction equations developed. Lastly, consideration should be given to the frequency of data collection, the need for standardization of data and other potential limitations of tools in the prediction of feed intake. This review summarizes measurements of feed efficiency, factors that may impact the efficiency and feed consumption of an animal, tools that have been researched and new traits that could be utilized for the prediction of feed intake and efficiency, and prediction equations for feed intake and efficiency presented in the literature to date.Feed for dairy cattle has a major impact on profitability and the environmental impact of farms. Sustainable dairy production relies on continued improvement in feed efficiency as a way to reduce costs and nutrient loss from feed. Advances in breeding, feeding and management have led to the dilution of maintenance energy and thus more efficient dairy cattle. Still, many additional opportunities are available to improve individual animal feed efficiency. Sensing technologies such as wearable sensors, image-based and high-throughput phenotyping technologies (e.g., milk testing) are becoming more available on commercial farm. The application of these technologies as indicator traits for feed intake and efficiency related traits would be advantageous to provide additional information to predict and manage feed efficiency. This review focuses on precision livestock technologies and high-throughput phenotyping in use today as well as those that could be developed in the future as possible indicators of feed intake. Several technologies such as milk spectral data, activity, rumen measures, and image-based phenotypes have been associated with feed intake. Future applications will depend on the ability to repeatably measure and calibrate these data across locations, so that they can be integrated for use in predicting and managing feed intake and efficiency on farm.

Few studies have attempted to quantify the association between a terminal total merit index with phenotypic feed and production efficiency in beef cattle, particularly when feed efficiency is itself explicitly absent as a goal trait in the index. The objective of the present study was to quantify the differences in phenotypic performance for feed intake, feed efficiency, and carcass traits of crossbred bulls, steers, and heifers differing in a terminal total merit index. A validation population of 614 bulls, steers, and heifers that were evaluated for feed intake and efficiency in the same feedlot and subsequently slaughtered at the end of their test period was constructed. The Irish national genetic evaluations for a terminal index of calving performance, docility, feed intake, and carcass traits were undertaken with the phenotypic records of animals present in the validation population masked. The validation population animals were subsequently stratified into four groups, within sex, according to their terminal index value. Mixed models were used to quantify the association between terminal genetic merit and phenotypic performance; whether the associations differed by sex were also investigated. The regression coefficient of phenotypic feed intake, carcass weight, carcass conformation, or carcass fat on its respective estimated breeding values was 0.86 kg dry matter 0.91 kg, 1.01 units, and 1.29 units, respectively, which are close to the expectation of one. On average, cattle in the very high terminal index stratum had a 0.63 kg DM/d lower feed intake, a 25.05 kg heavier carcass, a 1.82 unit better carcass conformation (scale 1 to 15), and a 1.24 unit less carcass fat score (scale 1 to 15), relative to cattle in the very low terminal index stratum. Cattle of superior total genetic merit were also more feed efficient (i.e., had a lower energy conversion ratio, lower residual feed intake, and greater residual gain), had a greater proportion of their live-weight as carcass weight (i.e., better dressing percentage) and were slaughtered at a younger age relative to their inferior total genetic merit counterparts. This study provides validation of an all-encompassing total merit index and demonstrates the benefits of selection on a total merit index for feed and production efficiency, which should impart confidence among stakeholders in the contribution of genetic selection to simultaneous improvements in individual animal performance and efficiency.

The practical usage of untraditional feedstuffs such as sunflower meal (SFM) in laying hens nutrition in developing countries has received considerable attention. SFM is a by-product of the sunflower oil industry and has been progressively added to bird’s diets. Sunflower meal (SFM) is gaining great interest as a feed ingredient due to its eminent crude protein content, low anti-nutritional compounds, and low price. The current experiment was aimed to assess the production efficiency, egg quality, yolk fatty acids composition, and nutrient digestibility of laying hens fed SFM. A total of 162 Bovans Brown laying hens aged 60 weeks old were randomly allocated using a completely randomized design into three experimental groups of nine replicates each (n = six/replicate) for eight weeks. The dietary treatments involved a control (basal diet) and two levels of SFM, 50 and 100 g/kg feed. The dietary treatments did not influence live weight gain, feed intake, and egg mass. On one hand, the laying rate was increased; on the other hand, the feed conversion ratio and broken eggs rate of laying hens were decreased (p < 0.05) by the dietary inclusion of SFM. Dietary treatments had no effect on the egg’s quality characteristics except the yolk color and yolk height were larger (p = 0.01) for laying hens fed SFM compared with those fed the control. Dietary inclusion of SFM decreased (p < 0.05) the content of cholesterol in the egg yolk. Still, it increased the yolk contents of vitamin E, calcium, linoleic acid, linolenic acid, and oleic acid (p < 0.05). Furthermore, the dietary inclusion of SFM increased crude protein and calcium digestibility, but decreased the ether extract digestibility. In conclusion, our results suggested that the dietary inclusion of SFM, up to 100 g/kg at a late phase of laying, could improve the production performance, some of the egg quality traits, and nutrient digestibility while decreasing egg yolk cholesterol.

The purpose of this study was to investigate the effect of the dietary mulberry leaves on nutrient digestibility and layer performances. The experiment was conducted for 30 days on 105 Lohman Brown layers assigned to 3 groups (C, E1 and E2) with 35 layers/group. The experimental diets included 3% (E1) and 6% (E2) mulberry leaves. The layers had free access to the food. The feed intake, egg production, feed conversion ratio, egg mass production and egg weight were recorded; no significant difference was noticed between the 3 groups. Digestibility studies were performed on weeks 2 and 3 (5 days/week). Organic matter digestibility was significantly higher in the control group compared to the experimental groups: E1 and E2. Nitrogen free extractives significantly differed in groups too. The physical parameters of the eggs (egg weight, egg white weight, egg shell thickness, Haugh unit, egg yolk weight and egg shell weight) did not differ significantly between the groups. Yolk colour intensity was significantly higher in the experimental groups E1 and E2 compared to the control group. Use of mulberry leaves in laying hens nutrition by including into ratio up to 6% had no negative effects on breeding performances and egg quality.

In total, 392 male broilers were randomly distributed in a factorial arrangement of 2 × 4, with two commercial broiler strains (Arbor Acres (AA) and Hubbard (Hub)) and four (NRC, Degussa, CVB, and strain guides) different feeding regimens (FR), totaling eight treatments and seven replicates, with seven broilers in each one. The following parameters were evaluated: bodyweight gain (BWG), feed intake (FI), feed conversion ratio (FCR), carcass yield, meat quality, nutrient intake, and its correlation with BWG. Interaction strain type × FR was significant for BWG, FI, and FCR, with the AA broilers showing higher BWG and FI and lower FCR than the Hub broilers. There was no difference in BWG, FI, and FCR of the AA broilers regardless of FR they were on, but the Hub broilers had lower BWG when they were fed according to the Degussa and CVB regimens; BWG and FCR were negatively affected. During the starter phase, BWG of the AA broilers was significantly correlated with feed, metabolisable energy (ME), lysine, and sulfur amino acids (SAA) intake. However, BWG was correlated with feed and ME intake and feed intake from 1 to 31 and from 1 to 42 days of age, respectively. In the Hub chicks, ME and crude protein intake and lysine and SAA intake were inversely correlated with BWG from 1 to 31 days and from 1 to 42 days of age, respectively. There was no significant effect of FR on dressed carcass weight or relative gizzard, pancreas, and liver weights and on intestinal weight; however, abdominal fat and spleen differed significantly with FR. Strain type significantly affected the relative weight of the intestines. There was no significant effect of FR and/or strain type on meat moisture, crude protein, lipid and ash content, or pH, colour, meat juiciness and tenderness (meat softness). In conclusion, AA strain of broiler performed better than the Hub strain under the different FR in all the evaluated production phases, but neither FR nor strain type affected carcass characteristics.

BackgroundFeed contributes to over 60 % of the total production costs in the poultry industry. Increasing feed costs prompt geneticists to include feed intake and efficiency as selection goals in breeding programs. In the present study, we used an F2 chicken population in a genome-wide association study (GWAS) to detect potential genetic variants and candidate genes associated with daily feed intake (FI) and feed efficiency, including residual feed intake (RFI) and feed conversion ratio (FCR).MethodsA total of 1534 F2 hens from a White Leghorn and Dongxiang reciprocal cross were phenotyped for feed intake and efficiency between 37 and 40 weeks (FI1, RFI1, and FCR1) and between 57 and 60 weeks (FI2, RFI2, and FCR2), and genotyped using the chicken 600 K single nucleotide polymorphism (SNP) genotyping array. Univariate, bivariate, and conditional genome-wide association studies (GWAS) were performed with GEMMA, a genome-wide efficient mixed model association algorithm. The statistical significance threshold for association was inferred by the simpleM method.ResultsWe identified eight genomic regions that each contained at least one genetic variant that showed a significant association with FI. Genomic regions on Gallus gallus (GGA) chromosome 4 coincided with known quantitative trait loci (QTL) that affect feed intake of layers. Of particular interest, eight SNPs on GGA1 in the region between 169.23 and 171.55 Mb were consistently associated with FI in both univariate and bivariate GWAS, which explained 3.72 and 2.57 % of the phenotypic variance of FI1 and FI2, respectively. The CAB39L gene can be considered as a promising candidate for FI1. For RFI, a haplotype block on GGA27 harbored a significant SNP associated with RFI2. The major allele of rs315135692 was favorable for a lower RFI, with a phenotypic difference of 3.35 g/day between opposite homozygous genotypes. Strong signals on GGA1 were detected in the bivariate GWAS for FCR.ConclusionsThe results demonstrated the polygenic nature of feed intake. GWAS identified novel variants and confirmed a QTL that was previously reported for feed intake in chickens. Genetic variants associated with feed efficiency may be used in genomic breeding programs to select more efficient layers.Electronic supplementary materialThe online version of this article (doi:10.1186/s12711-015-0161-1) contains supplementary material, which is available to authorized users.

In the last 10 years, there have been 3 major research and development projects in Australia on the efficiency of feed utilisation by beef cattle. The primary objective of these projects has been to examine individual animal variation in feed efficiency and its exploitation for genetic improvement in beef cattle. The results of these projects indicate that genetic variation in feed efficiency exists in Australian beef herds, that feed efficiency is moderately heritable and that the potential exists to reduce the cost of beef production through selection for efficient cattle. These results have been further developed for industry application through the generation of BREEDPLAN estimated breeding values for net (or residual) feed intake (a feed efficiency trait) for Angus and Hereford–Polled Hereford breeds. Although economic analyses have indicated substantial benefit from selection for feed efficiency, the high initial cost of identifying animals which are superior for feed efficiency is a barrier to rapid adoption of the technology. Developing cost-effective methods of implementing the feed efficiency technology is thus an on-going research activity. Challenges for the future include: the development and use of more sophisticated statistical analyses procedures (such as random regression) for feed intake and efficiency evaluation; development of accurate methods of assessing individual animal feed intake at pasture; the adoption of a whole-production system approach to feed utilisation; and better integration of the disciplines of genetics and nutrition. The outcomes from research in the efficiency of feed utilisation in beef cattle have wider applications, not only in other livestock species, but also in human energetics, such as the control of obesity.

Records on 78 steers and heifers were used to determine relationships among different measures of growth, feed efficiency and carcass traits, and to evaluate the effects of 2 preweaning growth rates on growth and efficiency in a feedlot. The preweaning growth rates [g/day; 871 (high) or 466 (low)] were imposed on the steers and heifers for 115 days before they were weaned at a mean age of 220 days. They were 'backgrounded' for 7 months on high quality pastures before finishing on grain-based diets in a feedlot for 85 days. The cattle were then slaughtered and carcass measurements recorded. Estimates were made on 10 growth and feed efficiency indices during the feedlot, and 5 carcass traits were assessed at slaughter. Of the indices, the Kleiber ratio which does not require measurement of feed intake (r = 0.98), was highly correlated with relative growth rate (RGR), as was feed conversion ratio (FCR, r = –0.82), which includes feed intake in the calculation. Residual feed intake, calculated using the expected feed intake estimated from the dataset (RFIREG), was correlated (r = 0.62) with RFI calculated from Australian feeding standards (RFISCA), and with FCR (r = 0.45). FCR was not correlated with either carcass rib or hot P8 fat depths but was significantly correlated with carcass weight (0.39), dressing percentage (0.41) and eye muscle area (0.33). RFIREG was not correlated with any of the 5 carcass traits. Whilst the average daily gain in the feedlot was similar between the 2 preweaning groups (1.544 kg/day), the low group was significantly (P<0.05) lighter at feedlot entry (323 v. 376 kg). Daily feed intake was lower (P<0.01) in the low group (10.9 v. 11.8 kg) such that the FCR tended to be lower (P<0.10) relative to the high group. Differences between the preweaning treatment groups were not significant for the other measures of feed efficiency. The results indicate that early life nutritional restriction has some influence on FCR in the feedlot, but little effect on those feed efficiency measures, such as RFI, that account for energy required for both maintenance of liveweight and growth.

Sustainability has come to play an important role in agricultural production. A way to combine efficiency with sustainability might be by searching for robust animals that can be selected for the homogeneity of certain traits. Furthermore, the optimization of feed efficiency is one of the challenges to improve livestock genetics programmes, but this might compromise reproductive efficiency. Animals from two divergent mouse lines, regarding variability of birthweight, were used to check whether homogeneity was also related to both feed and reproductive efficiency. The objective of this study was to use these divergent lines of mice to compare them with their feed efficiency and the reproductive capacity. Animal weight, weight gain, feed intake, relative intake and cumulated transformation index were considered as feed efficiency traits. Animals from the low line had both lower weight and feed intake from 21 to 56days. They had a worse transforming index in the three last weeks when litter size was fitted as an effect of the model, but the lines become similar if the higher litter size of the low line was not included. Reproductively, the low line performed better considering the number of females having parturitions, the number of parturitions, and with higher litter size and survival in both parturitions. Hence, the low variability line was preferred because of reproductive efficiency without seriously affecting its feed efficiency. Homogeneity seemed to be related to robustness with similar feed efficiency but higher reproductive efficiency.

ارزیابی کارآیی استفاده از منابع چربی اشباع و غیر اشباع در جیره بر عملکرد و لیپیدهای خون جوجههای گوشتی با دو سطح انرژی قابل متابولیسم

Genetic aspects of feed intake and efficiency in lactating dairy heifers

Feed in livestock production is a major cost driver and closely linked to GHG emissions from the sector. Hence, there is a great deal of interest to improve feed efficiency of livestock and promote economic and environmental sustainability of livestock production. We estimated feed efficiency of 48 early- to mid-lactation Norwegian Red dairy cows based on intake and performance data collected for 54 d using a stochastic feed requirement frontier (SFRF). The SFRF predicted the minimum feed intake each cow required to support its production and maintenance needs, accounting for parity, lactation stage, body reserve mobilization, unobserved cow-specific heterogeneity, and statistical noise. Feed efficiency of each cow was then estimated in 2 ways: first by computing a feed efficiency score as a ratio of the prediction from the SFRF to the observed feed intake of each cow, and second by computing surplus feed intake (SFI) of each cow as a difference between observed and predicted feed intake. Furthermore, it was shown that feed efficiency can be decomposed into time-invariant and time-variant parts. Results showed that the average feed efficiency score was 89.7%, and it was time-invariant for the period covered during the study. The score implies 10.3% of the observed feed intake was SFI. In absolute terms, the SFI amounted to 13.3 kg of DM/wk on average. However, cows in the least feed efficient quartile had SFI of almost 5 times higher than cows in the most feed efficient quartile. Furthermore, cow-specific feed intake variation accounted for only 53.9% of the total feed intake variation. The remaining 46.1% of the feed intake variation was due to statistical noise. Out of the cow-specific feed intake variation, 82.1% was due to differences in feed efficiency, whereas the remaining 17.9% was due to other sources of unobserved cow-specific heterogeneity. When implemented with lifetime data, the feed efficiency decomposition approach presented in this study enables understanding of the temporal trajectory of feed efficiency within and across lactations. Furthermore, it allows identification of feed efficiency that is repeatable over lifetime, facilitating the inclusion of feed efficiency in breeding programs.

ObjectiveThe feed intake (FI) and feed efficiency are economically important traits in ducks. To obtain insight into this economically important trait, we designed an experiment based on the residual feed intake (RFI) and feed conversion ratio (FCR) of a random population Pekin duck.MethodsTwo thousand and twenty pedigreed random population Pekin ducks were established from 90 males mated to 450 females in two hatches. Traits analyzed in the study were body weight at the 42th day (BW42), 15 to 42 days average daily gain (ADG), 15 to 42 days FI, 15 to 42 days FCR, and 15 to 42 days RFI to assess their genetic inter-relationships. The genetic parameters for feed efficiency traits were estimated using restricted maximum likelihood (REML) methodology applied to a sire-dam model for all traits using the ASREML software.ResultsEstimates heritability of BW42, ADG, FI, FCR, and RFI were 0.39, 0.38, 0.33, 0.38, and 0.41, respectively. The genetic correlation was high between RFI and FI (0.77) and moderate between RFI and FCR (0.54). The genetic correlation was high and moderate between FCR and ADG (−0.80), and between FCR and BW42 (−0.64), and between FCR and FI (0.49), respectively.ConclusionThus, selection on RFI was expected to improve feed efficiency, and reduce FI. Selection on RFI thus improves the feed efficiency of animals without impairing their FI and increase growth rate.

The ghrelin (GHRL), ghrelin receptor (GHSR), and insulin-like growth factor 1 receptor (IGF1R) genes have crucial effects on body weight (BW), body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR) in many species. However, few studies on associations of GHRL, GHSR, and IGF1R with BWG, FI, and FCR have been reported in chickens. In this study, 16 SNPs in GHRL, GHSR, and IGF1R genes were genotyped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The objective of this study was to examine the associations of GHRL, GHSR, and IGF1R genes polymorphisms with BW at 49 days (BW49) and 70 days (BW70) of age, BWG, FI, and FCR in the interval in two yellow meat-type populations with a total of 724 birds. The results showed that rs15675067 of GHRL was significantly associated with BW70, BWG, and FCR (P < 0.05). For GHSR, rs16675844 had significant effects on FI and FCR (P < 0.01), and that rs14678932 showed significant association with BWG and FI (P < 0.05). Rs14011780 of IGF1R was strongly associated with BW49, BW70, and FCR (P < 0.05). Furthermore, haplotypes based on three SNPs of rs14986828, rs15675067, and rs15675065 in GHRL were significantly associated with BW70 and FCR (P < 0.05). Meanwhile, a three-SNP haplotype comprising rs14011783, rs14011780, and rs14011776 in IGF1R showed significant effects on BW49, BW70, and FCR (P < 0.05). Therefore, it was concluded that the identified SNPs and analyzed haplotypes in this study might be useful for broiler breeding programs.