P. C. H. Morel

Preliminary investigation of the effects of low-level dietary inclusion of fragrant essential oils and oleoresins on pig performance and pork quality

Since the tissue characteristics of monogastric species are readily influenced by the composition of the feeds they consume, the objectives of this preliminary study were to assess the performance of finisher pigs on diets containing 0.05% of essential oils or oleoresins of rosemary, garlic, oregano, or ginger, and to determine the effect of these diets on pork quality. The pigs preferred the garlic-treated diet, and feed intake and average daily gain were significantly increased although no difference in feed efficiency was observed. Carcass and meat quality attributes were unchanged by dietary treatment, although a tendency towards reduction of lipid oxidation was noted in oregano-fed pork. Sensory panelists were unable to detect a flavour/aroma difference between treated and control pork. These results indicate that a higher level of dietary supplementation may be required in order to effect observable differences in pork characteristics.

Influence of stocking density on the performance, carcass characteristics and selected welfare indicators of broiler chickens

Abstract AIM: To compare the effects of four stocking densities (5, 10, 15 or 20 birds per m2) on the performance, carcass characteristics and selected welfare indicators of broiler chickens. METHODS: A total of 756 day-old male broiler chicks were assigned as six replicates of 13, 25, 38 and 50 birds per pen, to stocking densities of 2,000, 1,000, 667 and 500 cm2 floor space per bird, respectively. The birds were housed in floor pens in an environmentally controlled room. Normal commercial diets were fed ad libitum and fresh water was freely available throughout the 5-week study period. Liveweights of birds and feed intake were recorded at weekly intervals. Data on carcass parameters and welfare indicators (moisture, gait scores, feather scores, breast and hip lesions, and foot pad and hock burns) were obtained on Day 35. Adrenal glands were removed at slaughter, weighed and examined histologically to determine the total proportion of cortical and medullary tissues. RESULTS: During the study, the birds at the lowest density grew faster (p<0.001−0.01) and consumed more (p<0.001− 0.01) feed than those at the other three stocking densities. The liveweight gains and feed intake of birds reared at densities of 10, 15 and 20 birds per m2 were similar (p=0.11−0.83 and p=0.17−0.57, respectively). Stocking density had no influence on the feed/weight gain, mortality or carcass characteristics. No breast or hip lesions were observed in carcasses from any of the groups. The weight and structure of the adrenal glands were similar across all groups although the staining of medullary tissue of birds was most intense in the highest stocking density group. As stocking density increased, so did moisture and gait score, hock and foot pad burn scores, and the feather score was adversely affected. CONCLUSIONS: The data showed that the relationship between stocking density and productivity traits was not linear in nature, in accordance with other studies. Under the conditions of the current study, the performance, mortality and carcass characteristics of broilers grown at densities of 10, 15 and 20 birds per m2 were similar. There were some welfare implications at high population densities as indicated by adverse effects on litter quality, gait scores and the incidence of hock and foot pad burns.

The effect of modified atmosphere packaging with carbon monoxide on the storage quality of master-packaged fresh pork

Modified atmosphere packaging with carbon dioxide is effective for prolonging shelf-life of fresh meat. Addition of carbon monoxide to the system provides the advantage of enhancing meat colour. The study objective was to determine the effect of CO(2)-MAP+0.4% CO, vs. 100% CO(2)-MAP, on the bacteriology and colour of retail-ready fresh pork stored for 8 weeks in a master-package system. Total plate counts were not affected and listeria was present on meat from both treatments. Colour was enhanced with the inclusion of CO, while no effect on lipid oxidation was observed. Use of CO in MAP provides sufficient storage life and product colour quality to permit shipment of fresh pork to distant markets. However, given the stable fresh colour of CO-treated meat and the lack of inhibition of pathogen growth by CO, there is concern that CO-MAP under certain conditions may pose a food safety risk.

Influence of whole wheat feeding on the development of gastrointestinal tract and performance of broiler chickens

The main aim of the present study was to investigate the changes in the relative growth of digestive organs of broilers as influenced by whole wheat feeding and age of birds. The secondary aim was to examine the effects of whole wheat feeding on broiler performance over a 5-week feeding period. Diets containing ground wheat and whole wheat (100 and 200 g/kg whole wheat replacing ground wheat during 1-21 days and 22-35 days, respectively) were placed in 4 replicate pens (46 birds/pen) each. Throughout the 5-week trial, the birds offered feed containing wheat as whole grain grew slower (P 0.05) by the form of wheat during the first 2 weeks, but was significantly lowered (P 0.05) on the relative weights of crop, proventriculus, and pancreas or on the relative weight and length of the small intestine. The relative weights of storage sections of the gastrointestinal tract (crop, proventriculus, and gizzard) steadily declined during the 5-week period. The relative weights of pancreas and liver increased to Day 14 and decreased thereafter. The relative weights of intestinal segments were maximal during Weeks 1 and 2 of life, and declined rapidly with age. In general, the growth of different segments of the small intestine (duodenum, jejunum, and ileum) followed a similar pattern. The intestinal mass, measured as g tissue/cm tissue, steadily increased over the trial period, indicating that, although the relative size of the intestine declines with age, this decline is compensated by increased intestinal mass to support the nutrient supply function to the demand tissues.

Endogenous flow of amino acids in the avian ileum as influenced by increasing dietary peptide concentrations

The aim of the present study was to establish whether feeding broiler chickens with diets containing increasing dietary peptide concentrations would cause increases in ileal endogenous amino acid flow. The flow of N and most amino acids increased quadratically (P < 0.05 to 0.001) with increasing dietary concentrations of peptides. The exceptions were the flow of threonine, serine, glycine, tyrosine and cystine, which increased linearly (P < 0.001) with dietary peptide levels. Another notable exception to the general trend was the flow of proline, which was significantly higher (P < 0.01) in birds fed the protein-free diet. The amino acid profile of endogenous protein, expressed as proportion of crude protein, indicated that the ratios of threonine, glutamic acid, proline, glycine, leucine, histidine, arginine and cystine were influenced (P < 0.05) with increasing dietary peptide concentrations. In general, compared with the protein-free diet, the ratios of threonine and arginine in endogenous protein were lower (P < 0.05) and those of glutamic acid, glycine and histidine were greater (P < 0.05) in diets with high concentrations of peptides. The ratio of proline was found to decrease (P < 0.05) with increasing dietary peptide concentrations. These changes in the amino acid profile of endogenous protein are probably reflective of changes in the output of one or more of the components of endogenous protein. Overall, the present results demonstrated that increasing dietary peptide concentrations increased the flow of endogenous amino acid flow at the terminal ileum of broiler chickens in a dose-dependent manner and also caused changes in the composition of endogenous protein. The observed changes in endogenous amino flow will influence the maintenance requirements for amino acids and also have implications for the calculation of true digestibility coefficient of feedstuffs.

Quantitative fatty acid signature analysis on New Zealand sea lions: model sensitivity and diet estimates

Abstract We used quantitative fatty acid signature analysis (QFASA) to predict the long-term diet of New Zealand (NZ) sea lions (Phocarctos hookeri) incidentally caught in the NZ arrow squid (Nototodarus spp.) fishery. The QFASA model used fatty acid (FA) profiles based on 82 blubber samples of NZ sea lions bycaught between 2000 and 2006. First, the model was optimized by a series of simulations for which 1 model parameter—6 different sets of calibration coefficients (CCs) from different pinniped species and feeding regime, 2 sets of FAs, and the consideration of individual prey values, or mean prey values—varied each time. The best-fit parameters were those giving the lowest Kullback–Liebler distance values. Second, these parameters were used in a model to estimate the diet of NZ sea lions. QFASA was highly sensitive to the set of CCs applied. Across years the most important prey estimated with the best-fit CCs were southern arrow squid (Nototodarus sloani, 18–28% mass), hoki (Macruronus novaezelandiae, 10–27% mass), rattails (Macrouridae, 7–27% mass), and possibly scampi (Metanephrops challengeri, 1–19% mass). Despite the uncertainty on the accuracy of the match between the best-fit CCs used and the true FA metabolism of NZ sea lions, the variation of prey estimated among years was highly consistent with the trends of commercial catches during the same period, providing some confidence in the present QFASA predictions. The most important estimated prey were demersal species living mainly at depths >200 m that NZ sea lions encounter on the slopes of the Auckland Islands shelf. Our study emphasized the importance of these areas for bycaught NZ sea lions over the 1st half of the lactation period.

The influence of diets supplemented with conjugated linoleic acid, selenium, and vitamin E, with or without animal protein, on the composition of pork from female pigs

The objective of this study was to evaluate the effect of dietary manipulations on the fatty acid composition, Se content, and vitamin E content of pork. Sixty Duroc-cross gilts were randomly allocated at weaning to 1 of 4 dietary treatment groups (n = 15 per group). The 4 experimental diets were based on animal plus plant components or plant components only, with or without the inclusion of a dietary supplement (0.614%) containing CLA, Se, and vitamin E. The growth performance to approximately 100 kg of BW was similar with diets containing animal plus plant components or only plant components. Growth was also similar when either of these diets included the supplement. Inclusion of the supplement led to expected increases in Se and vitamin E contents (P < 0.001) of the LM. The differences found in the fatty acid profile of the lipid in LM, loin subcutaneous fat, and the belly cut (pork belly) between the groups with and without animal components in their diets largely reflected differences in the diet composition. Inclusion of the supplement led to greater CLA contents in all 3 tissues (P < 0.001), and also to lower contents of oleic acid (P < 0.001) and greater contents of stearic acid (P < 0.05), possibly due to an inhibition of stearoyl-CoA desaturase enzyme. The supplement also led to an increase in LM intramuscular fat (P < 0.05), but did not affect P2 fat depths (65 mm lateral to the midline of the spine at the last rib; mean depth of 11.8 mm). It is concluded that changing from a part animal component diet to an all plant diet will not change the growth performance of pigs but changes in the fatty acid profile of pork are likely to occur. It is further concluded that the nutritional value of pork may be successfully enhanced by simultaneously supplementing the diet with CLA, selenium, and vitamin E.

Invited review: organic and conventionally produced milk-an evaluation of factors influencing milk composition.

Consumer perception of organic cow milk is associated with the assumption that organic milk differs from conventionally produced milk. The value associated with this difference justifies the premium retail price for organic milk. It includes the perceptions that organic dairy farming is kinder to the environment, animals, and people; that organic milk products are produced without the use of antibiotics, added hormones, synthetic chemicals, and genetic modification; and that they may have potential benefits for human health. Controlled studies investigating whether differences exist between organic and conventionally produced milk have so far been largely equivocal due principally to the complexity of the research question and the number of factors that can influence milk composition. A main complication is that farming practices and their effects differ depending on country, region, year, and season between and within organic and conventional systems. Factors influencing milk composition (e.g., diet, breed, and stage of lactation) have been studied individually, whereas interactions between multiple factors have been largely ignored. Studies that fail to consider that factors other than the farming system (organic vs. conventional) could have caused or contributed to the reported differences in milk composition make it impossible to determine whether a system-related difference exists between organic and conventional milk. Milk fatty acid composition has been a central research area when comparing organic and conventional milk largely because the milk fatty acid profile responds rapidly and is very sensitive to changes in diet. Consequently, the effect of farming practices (high input vs. low input) rather than farming system (organic vs. conventional) determines milk fatty acid profile, and similar results are seen between low-input organic and low-input conventional milks. This confounds our ability to develop an analytical method to distinguish organic from conventionally produced milk and provide product verification. Lack of research on interactions between several influential factors and differences in trial complexity and consistency between studies (e.g., sampling period, sample size, reporting of experimental conditions) complicate data interpretation and prevent us from making unequivocal conclusions. The first part of this review provides a detailed summary of individual factors known to influence milk composition. The second part presents an overview of studies that have compared organic and conventional milk and discusses their findings within the framework of the various factors presented in part one.

Chemical composition characteristics of the longissimus and semimembranosus muscles for pigs from New Zealand and Singapore

A range of composition characteristics of the longissimus (LL) and semimembranosus (SM) muscles were compared between pigs raised in intensive and extensive production systems in New Zealand (NZ), and pigs raised in an intensive system in Indonesia for supply to the Singapore market (n=8/group). Ultimate pH was slightly higher for the Singaporean LL muscles (P<0.05), while LL muscle of the NZ extensive group was redder (higher a(∗) values) and contained more fat (P<0.05). Muscle iron levels were highest for the NZ extensive group and lowest for a lighter group within the Singapore pigs (P<0.05). Differences in fatty acid concentrations, which were also measured in a sample of the belly cut, could largely be attributed to the effects of diet, with higher levels of alpha linolenic acid for the NZ extensive group (P<0.05) due to linseed in the diet, and much higher levels of linoleic acid and the P:S ratio for the Singapore group (P<0.05). Some statistically significant differences in amino acid concentrations were shown between muscles and groups, but they were not large. With respect to compounds with potential bioactive properties, coenzyme Q10, and taurine levels were higher in pork from NZ pigs, and carnosine levels were highest for the NZ intensive group (P<0.05). The LL muscle contained more coenzyme Q10 and taurine, but less carnosine than the SM muscle (P<0.001). It is concluded that some of these composition differences in the pork from the muscles and groups compared may be of commercial importance, but several are likely to have been due to dietary or weight differences.

Proximate composition, energy content, and fatty acid composition of marine species from Campbell Plateau, New Zealand

Abstract Campbell Plateau is an important fishing ground for the main commercial New Zealand species. Yet, studies on trophic interactions between species and their nutritional values are limited. The objectives of this study were to determine the proximate composition and energy contents of selected commercial and non‐commercial marine species from Campbell Plateau and their fatty acid (FA) composition, and to evaluate the degree to which species can be differentiated by their FA compositions. We analysed 43 fish specimens from 5 different species (Macruronus novaezelandiae, Lepidorhynchus denticulatus, Pseudophycis backus, Hemerocoetes spp. and Squalus acanthias), 17 cephalopod specimens from 2 species (Nototodarus sloani and Enteroctopus zealandicus), and 6 Metanephrops challengeri (crustacean). The variation of energy contents between fish species was not significant, but their lipid and protein contents varied significantly. FA signatures distinguished the species analysed and, at a broader scale, the type of habitat. Within‐specie s variability was important for benthic species. In general, the diet inference from FA trophic markers was consistent with reported diets from stomach contents.